External Transmission Cooler Install (3rd Gen 4runner/1st Gen Tacoma)

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In this video, we share with you how I installed a Hayden 699 transmission cooler on my 98 Toyota 4runner. For this install, instead of running the cooler in-series with the stock cooler in the radiator, I chose to bypass the stock cooler. The way I installed this cooler would work for any 3rd Gen 4runner and also work for any 1st Gen Tacoma. If you have another make or model vehicle, hopefully this video gives you a good idea on how to accomplish the job. Happy Wrenching!
*Related Transmission Cooler Install Videos*
*Transmission Cooler Install on my 2000 4runner ran in-series with the stock radiator cooler: • Transmission Cooler In...
*Transmission Cooler Install on a 2008 FJ Cruiser bypassing the stock cooler:
• Transmission Cooler In...
*PARTS*
*Hayden 699 Transmission Cooler
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*Hayden Metal Mounting Bracket Kit
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*3/8" Transmission Cooler Hose - 3' (I'd suggest getting 6' so two orders of this).
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*Valvoline Max Life Full Synthetic ATF
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*3/4" Heater Hose - 6' (Used for abrasion protection)
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**Valvoline Max Life Full Synthetic ATF
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*Magnefine 3/8" Magnetic In-line Transmission Filter
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*This looks like a nice custom bracket for your trans cooler install. I learned about it on 10/12/23. It doesn't say it fits the Hayden 699 cooler, but it fits other cooler made by Hayden and one from Derale. iconic-fabrication.myshopify....
*HELPFUL TOOLS*
If you're looking for other tools not used in this video, check out Timmy's Master Tool List.
www.amazon.com/shop/timmythet...
*Scan Gauge (So you can monitor your trans temp)
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*Plastic Spudger Tool
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*1/4" and 3/8" Flex Head Ratchet Set
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*1/4" Drive Socket Set
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*3/8" Drive 6 Point Metric Standard Socket Set
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*3/8” Drive Regular Extension Set
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*1/4” Drive Regular Extension Set
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*Ball Pein Hammer
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*Milwaukee M12 3/8” Cordless Extended Reach Ratchet
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*Milwaukee M12 Battery
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*Milwaukee M12 High Capacity Battery
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*Milwaukee M12 Battery Charger
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*Adjustable Spark Plug Wire Puller
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*90 Degree Needle Nose Pliers
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*3 Piece Channel Lock Set
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*Small Pick Tool Set
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**As Ebay Partner Network members, we earn commissions from qualifying purchases.
**As Amazon Associates, we earn from qualifying purchases.

[@garywells3874]

Crazy, I was just looking for your old video on the B&M cooler because I wanted to install one on my Runner and found this video. This install looks solid and looks to have better cooling. Thanks...

[@TimmyTheToolman]

Yeah, this cooler is better than the B & M cooler I installed on my 2000 4runner years ago. I'm still not convinced bypassing the stock trans cooler is the way to go though I'll know better once I get my rig out on some trips this year.

[@garywells3874]

@@TimmyTheToolman The update on how the bypass is working would make a good follow up video. I get what you are saying about not being convinced but a pink milkshake would be a hassle. And it might be a little better cooling when you load the transmission off roading or towing.

[@TimmyTheToolman]

@@garywells3874 The cooler worked well on a recent trip to Death Valley. My trans temp didn't get super high but I did also use all the tricks I know like turning overdrive off and using 4Lo. The ambient temps while we were there weren't that hot either. We took a route north home through the Kirkwood area over a pass and we ran into a snow storm. My trans temp stayed pretty low, like low 100's. That wasn't exactly a great sign to me letting me know that internal pressure bypass doesn't work as well as I would have hoped. But, I think the B&M cooler ran in-series with the radiator cooler would have also had my trans temp low too. So, I probably wouldn't recommend this system or any external cooler system to anyone who drives a large portion of the year in a cold climate. I have heard people just throwing a piece of cardboard in front of the cooler to limit the air flow when they know they are going to be driving in really cold weather like I was that night. It's really hard to have a system that's good for all ambient temperatures. The big killer of transmissions is heat so keeping the temps lower is the biggest goal in my opinion.

[@SoChillExplores]

This is so dope Tim ! Thanks for sharing all your knowledge

[@TimmyTheToolman]

Thanks for the comment, and you're very welcome.

[@julioarrecis666]

Your videos are awesome!!!! i watched your videos over and over because the way you explained is clear as water. BTW. NICE T4R.

[@TimmyTheToolman]

Hey Julio, thanks for the nice compliment of our channel. I'm also glad you like my rig. Happy Wrenching!

[@3G4Runner_N_Gunner]

Thanks for the vid. I bought the 599 for my 02. Recently picked it up so I'm focusing on maintenance items and such. Plan to do this cooler mod once it warms up and eventually throw a new oem radiator in as well.

[@TimmyTheToolman]

You're welcome. Good luck with the job when you finally get around to doing it.

[@SSGHondaJon]

Thanks for the video guy. I dig the brackets.

[@TimmyTheToolman]

You're very welcome.

[@on-site4094]

Great idea on the bypass on the radiator & installing a trans filter another sic custom mod 👍

[@TimmyTheToolman]

Thanks, glad you like the Sic Mod.

[@caucasianafrican1435]

These videos could not be any better.

[@TimmyTheToolman]

Thanks. We appreciate your nice compliment of our work.

[@aldenjames7333]

Very good explanation of the work you performed. I subbed to your channel. 👍

[@TimmyTheToolman]

Glad you like the video Alden. Thanks for subscribing!

[@moviegear]

What a man that Timmy! Big thx for this upgrade!

[@TimmyTheToolman]

Thanks and you're very welcome!

[@stevefuller3585]

Another benefit to using Hayden coolers is the amount of airflow you get past the cooler due to their thin, flow through design. I love these coolers. I have two Hayden’s running parallel on my 2005 Z71. I went through many set ups before I came across them. Great video!! Very informative and well done.

[@TimmyTheToolman]

Thanks for the comment and glad you like the video.

[@edwinalexander1170]

Are they so effective in cooling ???

[@stevefuller3585]

@@edwinalexander1170 I would not have commented if they were not. Yes, they are very effective at cooling.

[@edwinalexander1170]

@@stevefuller3585 But it is suggested for effective cooling Hyden 526 with the moving fan, controlled by thermostat is more effective in cooling.

[@0341stroker]

Great mod. My transmission loved it when I was in the idaho mountains

[@TimmyTheToolman]

Yep, an external transmission cooler is a necessary mod for anyone that does mountain driving. Your transmission thanks you.

[@ever2gut1]

digging the message on the whiteboard ha!

[@TimmyTheToolman]

My wife wrote that. I guess she likes Timmy the Toolman.

[@tanner6245]

Will definitely consider this mod - I'm currently seeing temps easily hit 210+ on my 02 4runner with armor while out on the trails. Thanks Timmy!

[@TimmyTheToolman]

I'm going to test it out in Death Valley at the beginning of March which will let me know if I'll continue to run it bypassed or switch it to run the Hayden cooler in-series with the stock radiator cooler.

[@genxiong2695]

@@TimmyTheToolman Tim, did you change back to in-series? Typically, if you have a new radiator, it's not necessary to run by-pass as most people do it to avoid the pink milkshake. Toyota runs it in series for those truck that come with trans cooler. Let me know. Thanks

[@TimmyTheToolman]

@@genxiong2695 I'm still running it bypassed for now and I might leave it that way. I want to see how it does in hotter temps this summer. I have the cooler for my 2000 4runner in-series with the radiator cooler.

[@genxiong2695]

@@TimmyTheToolman Thank you for the quick reply. Just bought the exact cooler and will be installing. I will be running in series since I have a fairly new radiator. How's your temp running with this cooler compared to the one you took off? Did you see an improvement?

[@Squitszn]

@@TimmyTheToolmanhi Timmy just wanted to see if you were still running it bypass

[@stevenisacoolname2]

Nice work!

[@TimmyTheToolman]

Thanks Stevo!

[@shaunmilor]

I ruined a stock radiator in my supercharged 03 tacoma exactly the way you said, Using those plastic through radiator ties holding on an electric fan. I now have aluminum brackets bolted through the shroud holding it on. Has worked great for over 5 years. I have a manual trans so I dont have a trans cooler, but I did buy a big Hayden 1040 engine oil cooler meant for an f250. I built brackets that hold it as close to the grill I could get it. my coolant temp is almost never over 190 on hot summer days and stays at 172-176 in the winter. only time it goes over 190 is charging up hills pushing a ton of boost

[@TimmyTheToolman]

Thanks for sharing your experience.

[@mattedwoods]

About to fit one on my Toyota Prado 1996 as there is issues the cooler in the radiator fail and put coolant in the gear box and they are history So save the accident putting a separate cooler in so great video thank you

[@TimmyTheToolman]

You're very welcome Matt. Good luck with the install.

[@Patrick.Weightman]

You guys rock! Happy trails

[@TimmyTheToolman]

Happy Trails back at ya!

[@dothiswithme]

Hey Tim! First of all, thank you for all the educational videos you put out there. You saved me so much money teaching me to wrench my truck! I love how you explain the "why" in "how things work" if that makes sense. Anyway in the other video where you installed the same 699 cooler on the FJ, you mentioned that it did NOT have a thermal bypass valve. So would you say the 699 is safe to use it IN SERIES with the stock cooler (radiator) rather than bypassing? I know there's other models that do not have the thermal bypass, but the 699 is the closes size to the oem. I've been replaying 3:05 to 3:40 trying to understand. I'm basically replacing the old worn out one in my 100 series Land cruiser.

[@TimmyTheToolman]

Maybe I misspoke in the other video. The Hayden 699 cooler does have a bypass. How well it works, I don't know. It works based off the thickness of the fluid. When the fluid is cold it is thicker, and will bypass the thinner cooler channels until the fluid warms up and thins out. There isn't an actual thermostat opening and closing based off the temp of the fluid. You could definitely run it in-series with the stock cooler in the radiator.

[@stco2426]

Like the CAD - Cardboard Aided Design

[@TimmyTheToolman]

Yes, I thought Thanh's idea was a good one as well.

[@brycethoreson9216]

Thanks Tim

[@TimmyTheToolman]

You're welcome Bryce.

[@soapynorton]

Hi Timmy! Thanks for all of your time creating these excellent videos. I've watched many over the years! For some data points, I installed a B&M cooler on my 2000 in 2012 with around 120k miles and in the last 4 years, watched my transmission fluid temps reach 250° (peak) when climbing passes in the mountains often. I bypassed the OEM cooler like everyone talks about for fears of the dreaded radiator “design flaw” we all know. This was a hot topic in 2012. At around 230k miles and 10 years later, the trans ended up failing because of those consistent high temps and I replaced it with a lower mileage used one. In the last year with this new-to-me transmission, I’m still seeing high temps (~230+°) when climbing mountain roads even in the winter, so I think the auxiliary cooler alone is not sufficient for my rig. Maybe sufficient for others, but that’s not what I’m seeing. Im not running any armor, and have 32" tires. So I am wondering how this cooler is working for you and since you have both setups, would you run this bypassed setup with Hayden 699, or run in series with a smaller Hayden 679? I appreciate the time! T4R4Life!

[@TimmyTheToolman]

Even with running the B&M cooler in-series with the stock cooler on my 2000 4runner, I can see high trans temps going up steep and sustained mountain roads. The cooler can only do so much. There are tricks to keeping the temps down like turning overdrive off and using 4Lo while climbing sustained grades while 4wheeling. I've made videos on both techniques. kzbin.info/www/bejne/eHa9l3eFoKyJpNE kzbin.info/www/bejne/raLblo2soc-MfcU So, when driving these mountain passes, are you turning overdrive off? As long as you can maintain around 45 mph over those passes, turning overdrive off will help a ton with your trans temp. It will keep them at a nice normal operating temp. For really steep mountain roads where you can't maintain the speed to stay in 3rd gear, turning overdrive off won't help you. About the best you can do is put the trans in 2nd gear to raise the engine rpms to pull more air through the cooling fins. 250 degrees is high. When I'm climbing a grade, 230 degrees is the point at which I start to consider pulling over and giving my transmission and engine a break. When the temps drop quite a bit, I continue up the grade. The whole reason to monitoring your temps is to know when it's prudent to give your rig a break and to know when a problem has surfaced like maybe a trans cooler or radiator coolant hose has burst. I recently bypassed the stock trans cooler in my 98 4runner and I'm using a larger cooler, the Hayden 699. So far, my trans temps are looking good. If you still want to be bypassed to avoid the pink milkshake, I would suggest going to a larger cooler like this one. I made a video of the install. kzbin.info/www/bejne/aWXan5mnbZqSp80 I hope this information helped you out.

[@soapynorton]

@@TimmyTheToolman Well said! You know your stuff. I have had such similar experiences. When my transmission temp goes north of 200 degrees, it is typically when I am climbing curvy, sustained mountain roads under 30mph, with OD off. 60mph mountain passes with OD off is not a problem currently and I love those tricks. I am really looking for best cooling results for that sustained, less than 30mph scenario. Because I am in this scenario frequently, I really want to find a lasting solution and not have to watch so prudently to pull over and let cool. It sounds like your results with the smaller B&M cooler installed in-series is less efficient than the larger, bypassed 699. Is that accurate? Thanks!

[@TimmyTheToolman]

@@soapynorton I think the Hayden 699 bypasssd is doing better than the B&M ran in-series. You might want to try the Hayden 699 bypassed first and see how your trans temps do. If you're still experiencing high temps, maybe run the cooler in-series with the stock cooler. I know this will put you at risk of a cooler failure and resulting transmission damage but I think the pink milk shake is pretty rare.

[@soapynorton]

@@TimmyTheToolman Thanks for the guidance and experience Timmy. I will order a 699, install it and see how it goes. Sounds like the different fin design and extra size will be an upgrade. I was planning to hook up my original B&M cooler to the factory radiator to increase cooling power since I have a new radiator, but I will try the bigger Hayden 699 before hooking it up in-series. Will report back in due time!

[@jonnytacooutdoors]

Did you use a tru cool ? Long?

[@cal48koho]

Thanks Timmy for the tip on the Hayden 699. My question is why you went to the trouble to isolate the cooler on fabricated brackets. Hayden sends their own pass thru components with foam pads to isolate the cooler. This is the way I have installed coolers on previous vehicles. I decided I would just use their supplied parts. The job went well. I did not have to relocate any components and the whole job took only a bit over an hour. Am I missing something on advantages and disadvantages of doing the job the Hayden way? Your gauge install was super well done and I plan to follow it to a T.

[@TimmyTheToolman]

The reason I went with brackets and didn't use the supplied zip ties with foam pads, is because with enough vibration, those zip ties with the foam pads can work loose a bit. When that happens, the cooling fins for both the AC condenser and radiator can start to take further damage. If the cooler can move around enough, it could damage one of the cooling channels or the AC condenser or radiator which isn't exactly good. I've 4wheel my rig a decent amount and end up driving on washboard fire roads. Washboard fire roads cause a lot of vibration. If you don't 4wheel much and drive roads like that, you're probably good with the zip ties and foam pads. If you do 4wheel a lot of bumpy washboard roads, you might want to reconsider your mounting choice. Good luck with the trans temp gauge install.

[@georgegastellum8351]

Great Instructional Video! What trans temp sensor did you use for the t-fitting?

[@TimmyTheToolman]

Check out this video: Transmission Temperature Gauge Installation kzbin.info/www/bejne/nIXCY6awmbCLiK8

[@firemaniac]

I did something similar with my 04 Tacoma. I used a similar sized Hayden cooler, but without the built-in bypass, instead using a Derale bypass thermostat inline with the send and return lines. I also added an electric fan, on a temperature switch (190 on 170 off). Fully loaded, and towing my teardrop trailer, OD off, torque converter locked up, I maintain 165° on average. Balls to the wall, climbing mountain passes, in summer, (WA state) highest I saw was 210, and that came down reasonably quickly. A side effect, my coolent temperature remained fairly steady, as the transmission wasn't heating it up as well, 3 core aluminum radiator might have had something to do with that as well.

[@TimmyTheToolman]

The electric fan is something I considered and maybe I'll do it one day. Your trans temps sounds really good, especially with towing a trailer. My 98 is loaded down with lots of extra weight from bumpers, armor, roof rack and other mods so it's a tank. I'll be putting my rig through the paces with some off-road trips this year to help me access if my current set-up is a good one.

[@bluesky-ud9wg]

210 is too high. Should keep max temp no higher then 180

[@firemaniac]

@@bluesky-ud9wg everything thing I have read says 210 is on the hot side of the average range, 230, pull over and let it cool down with the engine running, 250, starts to harden the rubber seals, and the start of permanent damage range, and 300 will warp some parts. I am okay with 210 as a Max temperature, with 165 as the average running temperature.

[@bluesky-ud9wg]

@@firemaniac I stick by my saying 180-185, no higher

[@TimmyTheToolman]

@@bluesky-ud9wg You're dreaming if you think you can keep the temps from going no higher than 185. Anyone who travels in the mountains knows this is impossible. You will sometimes go into the 200's, especially if the ambient temps are very hot. The key is to know when it's prudent to pull over and give your transmission a break. The temp at which I start to consider pulling over is 230.

[@andres90789]

Timmy, thanks so much for your video. Im planning to install a hayden 678 on our honda pilot. It came with a small factory trans cooler but we had some overheating issues towing last year. If it fits can you think of any reason to install this as a second cooler vs. taking the smaller one out and installing a Hayden? Thanks so much, also does it matter if the filter is on the send vs return line? What is the benefit of bypassing the radiator?

[@TimmyTheToolman]

You can add the Hayden cooler as a second cooler or as a replacement. It's up to you. You'll obviously get more cooling using both. You can put the filter in the send or return line. It doesn't matter. With bypassing, you eliminate the chance of destroying your transmission if the OEM cooler in the radiator cracks. This allows engine coolant to mix with the ATF. Automatic transmissions don't like water and they fail , causing an expensive repair. It's not that common, but it happens. The downside to bypassing is that the ATF takes longer to get to operating temp. The cooler bathed in the coolant assists the fluid to get warmer faster. Lots of people just renew their radiator to prevent a trans cooler failure.

[@rangerdoc1029]

Super simple solution to the zip tie mount is to just put rubber grommets between the coils. Now no rub through risk.

[@TimmyTheToolman]

Yes, the kits come with rubber pads but if the zip ties aren't tight enough or get loose like I've seen happen on my own rig, the zip ties could cause damage as the cooler vibrates and moves around. I'm of the opinion that the zip tie mounting option isn't the best way to go.

[@kakaora1262]

Great videos. I have. 2003 Ltd 4runner and want to add a power steering cooler. Looking at using a Trans cooler for the add on. Pros and cons. The Hayden 699 looks like it would work. Thanks

[@TimmyTheToolman]

The 699 cooler might be overkill for a power steering cooler. I think you can get away with a much smaller one unless you plan on driving in the Baja 1000.

[@kakaora1262]

@@TimmyTheToolman thanks for the quick reply. Any specific part number you suggest? Been watching some of your videos. Most projects I want to do you have a video in. 👍👍👍

[@TimmyTheToolman]

@@kakaora1262 The B&M cooler we use in this video kzbin.info/www/bejne/aJ-5k6qbZ9lliposi=tFVnKddv7ZB7Z-ZY might work out well. It's linked in the video description.

[@albrownphotos]

Great Tutorial as always your videos are very helpful. Appreciate it. I do have a question on the longevity of the Hayden 699 transmission cooler. When will I need to replace that you think and will be there any signs beforehand? thank you.

[@TimmyTheToolman]

There's not a whole lot that can fail with a cooler. The cooler is painted so corrosion shouldn't be an issue. It should last the lifetime of the vehicle unless you get into a front end collision.

[@TimmyTheToolman]

Well technically unless it is leaking it should still perform as expected unless there is some type of clog. You can also replace it as a type of preventative maintenance but unlike a radiator, there is no real fear of it failing internally and mixing coolant with trans fluid as the trans cooler only has transmission fluid. - Sean

[@albrownphotos]

Thank you for your fast reply and sounds good! I’m planning to add the cooler with my next radiator replacement.

[@yotagang3705]

Hey Tim I have my trans temp sensor hooked to the return line as opposed to the sent line, is this fine? I watched your trans temp gauge install

[@TimmyTheToolman]

You will be reading the temp after it's been cooled so it won't be an accurate reading of what your trans temp actually is.

[@yotagang3705]

Timmy can you do a methanol cooling install for a supercharger? thanks

[@TimmyTheToolman]

Maybe one day Pauly.

[@erikschutzman2402]

Hello Timmy, do you know if the internal transmission cooler is on the cooler side tank or hotter side tank of the radiator? thank you

[@TimmyTheToolman]

The lower part of the radiator where the trans cooler is located is the cooler side of the radiator. The hot coolant enters the top of the radiator, is cooled and returns to the engine via the lower radiator hose.

[@badgersandcats2829]

I’m thinking of doing a trans cooler on my 1999 4Runner. I was wondering if your engine operating temperature was affected after adding the trans cooler. I would like to add this but don’t want to to trade lower tranny temps for higher operating temps. Thanks!

[@TimmyTheToolman]

No, my engine temps haven't suffered as a result of installing the trans cooler.

[@bigafhat]

Hey Tim, did you happen to add any more fluid to the system after you installed the cooler? Any way to bleed any air out or just leave it?

[@TimmyTheToolman]

Yes, you have to add fluid. You lose fluid when you disconnect the cooler hoses and you also now have a larger system capacity by adding the cooler. You don't have to bleed the air. It's not like a brake system that can't have air in it. The air just gets pushed back to the transmission. There is actually a breather on top of the transmission that lets excessive air pressure escape when the transmission gets hotter.

[@Nessal83]

Need to do this when my OE rad goes

[@TimmyTheToolman]

Well, hopefully you radiator doesn't go while you're out in BFE (Bum Fuck Egypt). Replace it as preventable maintenance for the peace of mind.

[@Nessal83]

@@TimmyTheToolman yeah like Death Valley lol. It's 18 years old but no signs of leaking.

[@toyotatim2521]

Your stock cooler that is in the bottom of the radiator is the same setup as my UK 1999 KZJ 95 Landcruiser, do you ever come across issues with the cooler or rad failing where they join and the transmission fluid and coolant mixing causing damage to the transmission? It seems to be a common problem and I replaced the radiator on mine at 120K miles to be safe. I was thinking of bypassing the stock cooler and fitting a stand alone trans cooler, what are your thoughts

[@TimmyTheToolman]

The trans cooler failing in the radiator does happen on these vehicles. How common it is, I don't know. They call it the "Pink Milkshake" because the mixing of the coolant and the ATF makes a frothy pink mess. Bypassing the stock cooler removes this from being a possibility. This was part of my decision to bypass the stock cooler.

[@bd604]

hey just a note that the Iconic Fabrications bracket you mention there will NOT fit a 699, as the 699 is considerably larger than the 698. Best to use the mounting bracket kit you linked. going to give this a go this weekend, thanks for the video.

[@TimmyTheToolman]

Good to know! Thanks for the info. - Sean

[@PrimerBravo]

awesome video! Did you bypass just to avoid the pink milkshake? Im have a champion radiator and am leaning towards running in series. Also, is there a reason you choose not to mount the trans cooler on passenger side facing the passenger direction? Just curious since the both the return and send lines are on that side of the vehicle?

[@TimmyTheToolman]

Yes, I bypassed to prevent a trans cooler failure destroying my transmission. I wanted to see if I ran a big enough stand alone cooler, would it sufficiently keep my trans temps at a good range. For the most part it has. It's still hard to avoid high temps in certain situations like climbing a steep mountain road in hot ambient temps. The reason why I mounted the cooler on the driver side was for the space available. From what I remember, there was less stuff in the way on the driver side.

[@PrimerBravo]

@@TimmyTheToolman Great, thank you for the response, love the videos they've been an amazing resource! I'm replacing my radiator with an aluminum champion and am leaning towards running in series. I tow a microlite camper into the mountains fairly often and live in Arizona so battling the heat and elevation!

[@joeshunt6416]

​please i need help. My mechanic installed the trans cooler with the hoses facing downward. Is that a problem?? because i feel like there hasnt been a change in trans temp..

[@TimmyTheToolman]

I think I remember upside is considered an acceptable position to mount it in, but I've only every done a sideways install with it filling from the bottom and exiting the top. You fill from the bottom so air is pushed out of the cooler and not trapped affecting the cooling efficiency of the trans cooler.

[@user-gs5wo4zt8q]

I’m hot areas like phx, az do you think this will affect the ac condensers performance?

[@TimmyTheToolman]

It shouldn't negativity affect your AC system enough to notice. The air will flow through the trans cooler and reach the AC condenser.

[@m.t.02]

Hey Tim- are there any concerns of the trans not getting up to temp or being too cooled by bypassing the radiator, especially in the colder months? I live in the Bay Area as well

[@andyloechler9896]

if your worried about warmup? install a thermostatic valve with a 180 temp, this way noting goes thru the cooler unless the ATF is a min of 180 deg. This is the only way to ensure consistent temps.

[@TimmyTheToolman]

The cooler like I mentioned in the video has a pressure bypass. When the fluid is colder and thicker, it won't pass through all the possible cooling fins until the fluid warms up and thins out. This helps the trans reach a better operating temp quicker. It's debatable how much the radiator cooler helps with raising the temp of the ATF. I have two 3rd Gens, one with the external cooler ran in-series with the stock cooler, and the one featured in this video that has a stand-alone external cooler. Even with the rig that has the external cooler ran in-series with the stock cooler, it can take quite a bit of time for the trans temp to rise. From my experience, what truly makes the trans temp rise is a load on the transmission, (ie climbing a hill). Putting a load on a trans is the quickest way to get it to an optimal operating temp. Cruising down the highway with a light load on the trans, it can take quite a while for the temp to rise.

[@firemaniac]

I use a thermostatic valve in my system, and I haven't observed any longer, or shorter times to warm up, besides the seasonal differences. I think where the bypass, or thermostatic valve especially helps is in colder temperatures (I was in Western Washington, now NW Montana) to maintain the lower operating temperature after it does warm up. In a more arid environment, it may not be needed.

[@nickg374]

Hi Tim, just curious on your take comparing your 2000 Toyota 4runner (in-series external transmission cooler) versus your 1998 Toyota 4runner (bypassing the radiator). Is there any big differences besides avoiding the possibility of the transmission milkshake? What are the major differences in temperature when offroading or towing between the two different setups? Your insight is always appreciated and can't wait to see more of your videos!

[@TimmyTheToolman]

I'd say the set-ups are comparable with the temperatures I'm achieving but these rigs are very different than each other in the area of weight. My 98 is considerably heavier than my stock 2000. It's probably at least 700 lbs heavier. The biggest advantage with running the larger external cooler bypassed on my 98 is I'm eliminating the chance of a trans cooler failure and ruining my auto transmission (pink milkshake). The only thing I've ever towed with either is a light motorcycle trailer, which probably weighed somewhere around 500 lbs. I told myself if I wasn't liking the temps I was seeing with my 98, I'd go back to running it in-series with the radiator cooler, but so far, I'm happy with what I'm seeing. I don't know if this helps you make your decision on which way to go, but hopefully it does.

[@nickg374]

@@TimmyTheToolman This was great insight! Thank you!

[@TimmyTheToolman]

You're welcome.

[@tomb6319]

Another great video. I literally have two of these coming in the mail for my Tundras and stumbled upon your video. I purchased them to completely bypass the stock trans cooler within the radiator to avoid any risk of pink milkshake. In your video you discussed why you oriented the cooler the way you did, to allow air to rise and escape. If you rotated the cooler 90 degrees so both the inlet and outlet faced downwards, do you think some air still may get trapped inside the cooler? I feel like there is still a slight possibility.

[@TimmyTheToolman]

I never done the fully inverted installation but I've heard of people doing it. I think the fear of getting air trapped is overblown but I wanted to cover it in the video because that's what I've read from at least one manufacturer of these coolers.

[@tomb6319]

@@TimmyTheToolman Thanks for the reply! I appreciate it. I got the coolers in the mail today and it appears there is not a designated inlet and outlet side on the cooler, am I correct in saying that?

[@TimmyTheToolman]

@@tomb6319 Yeah there is no identified inlet and outlet. The fluid could flow in either direction. There's just what I said in the video about air getting trapped based off how you mount it.

[@tomb6319]

@@TimmyTheToolman Awesome thanks for all the help Timmy, super excited to get these on my Tundras this weekend.

[@TimmyTheToolman]

@@tomb6319 No problem.

[@mtnbkr777]

Timmy - what kind of trans temps (pre cooler install) were you seeing on your climbs? On pavement at highway speeds on pretty steep mountain passes, my stock gen 2 Tacoma gets up to 215.

[@TimmyTheToolman]

In hot ambient temps on a steep grades, I could hit over 230 no problem. I'm talking traversing steep mountain roads at slower speeds, not highway speeds. When you're at highway speeds, it's much easier to keep your trans temp down by turning overdrive off to get the torque converter to lock up.

[@04tacomaguy1]

@@TimmyTheToolman I though with overdrive off the torque converter never locks up. Isn't 45 mph when rpms drop a lot overdrive gear ? I call it the gas saving gear its the only one my truck can get decent mpg in

[@TimmyTheToolman]

@@04tacomaguy1 The torque locks up with overdrive off and that's why the trans temps drop dramatically. With the torque converting spinning internally, it creates lots of heat.

[@04tacomaguy1]

@@TimmyTheToolman wow I must have had it backwards in my head all along. Which is embarrassing since I took a class on auto trans lol. I always thought when I went into overdrive the converter would lock. Around 45 mph or so and then the trans would run it’s coolest and the mpg would be the highest at the lowest rpm in overdrive.

[@TheBlakeSteinke]

Thanks Timmy! Installed this cooler before my cross country move+1000 miles off road in my 2004 Tacoma. Tena were really good compared to not having it especially in the mountains of Colorado. Despite having this cooler, the temps still got up to about 220 in some of the high mountain passes. Was brainstorming and thinking of putting a small fan on it. Do you think this would be effective?

[@TimmyTheToolman]

Even with an external trans cooler, your trans temps can go pretty high depending on the conditions. Slow steep climbs are the biggest enemies. With climbs, if you can maintain at least 45 mph, turning overdrive off will keep the temp down. Slower than 45 mph, the torque converter won't lock up with overdrive off, and the temps will climb. I don't know how much an additional fan will do. The fact you monitor your temps is more than half the battle. Sometimes, it's prudent to pull off and give your trans and engine a break. 220 degrees is not that bad. When you get over that though, it's time to consider pulling off the road and taking a break.

[@TheBlakeSteinke]

@@TimmyTheToolmanthanks for such a quick reply. I was thinking the fan may be a little more work that what it’s worth. Second note: got my koyorad radiator in today. Thanks for the videos, I’ve watched hours of them.

[@TimmyTheToolman]

@@TheBlakeSteinke You're very welcome. Good luck with the radiator swap.

[@yotagang3705]

Tim so I want the b&m transcooler whats the pn? Also I dont want to bypass, let me run this by u and let me know if this is correct; send line to bottom radiator exit to return that will then go to bottom line on external then out the top back to the trans? Thank you Tim.

[@TimmyTheToolman]

Yes, that is correct.

[@rthomas2157]

Thought I would add this, for those looking into doing this on a first GEN Tacoma. My truck is a 2003. I found out after removing my grill I had some AC lines running directly in front of the AC core that prevented me from mounting the cooler in this spot that you see Tim mounting this one. Tim I tried to watch the video again and see if you had these lines behind the cooler but I couldn’t see if you did. I cannot remember if the 3rd gen 4 runners had these lines there as well or not? I am thinking maybe some of the earlier year4 runners & Tacoma’s may be did not have these lines there. Anyway what I found is that I tried to slide the cooler back towards the center or directly behind the cross brace. What I found is that I had a AC line running behind that cross brace and after looking at your video I believe this line should be in front of or on the outside towards the front of the truck side of that Cross brace. Looking at a friends truck that line did run in front of that cross brace. I removed the cross brace so I could position it behind that line placing the line in front of it but found that when I re-tightened up the cross brace part of it was pressing against the cooler. I didn’t want this ultimately ending up rubbing a hole in the cooler so I slid the cooler all the way over to the left side or passenger side I found that this allowed for the best clearance of that center across brace so that it wasn’t pushing up against the cooler. Also found that I could use to existing bolts/screws holding in the AC condenser on the left side to attach brackets to then running them to the actual cooler. On the right side I am going to have to take Tim’s lead and drill a hole in the cross brace to attach brackets on that side. Anyway just thought I would share my experience of trying to find the best place to mount this on a first GEN Tacoma.

[@rthomas2157]

Edit: AC lines running in front of AC Condenser not core on The right side or driver side.

[@TimmyTheToolman]

The only AC line on the 3rd Gen 4runner runs in front of the cross brace. It goes from the AC condenser to the receiver/dryer on the passenger side.

[@rthomas2157]

Makes sense then why are you were able to mount yours on that side. I couldn’t remember if there were additional AC lines running there on 4 runners or not. On my truck I have two lines they’re making a C or U shaped bend Preventing me from mounting the cooler on that side

[@rthomas2157]

Tim I made a post on Tacoma world in the first GEN forum called external transmission cooler mounting location asking if other people had done this on their trucks and how they mounted it and in what location. I can post pictures there of the lines I’m talking about if you have any interest in looking at that. Thanks for your response.

[@TimmyTheToolman]

@@rthomas2157 Interesting. I don't understand how your 1st Gen Tacoma would be different. The 1st Gen Tacomas and 3rd Gen 4runners are almost identical when it comes to the front end. I guess this is one difference I didn't know about.

[@miguel2592]

What about the Hayden 679 or 678, I see they are the most popular picks on amazon, any thoughts?

[@TimmyTheToolman]

I don't know what's popular. The Hayden 699 was recommended to me by a friend who's installed them on several rigs. I looked at it, and it seemed like a good way to go.

[@cafesami9356]

My SUV reached the 200K milestone!!!! The combination of Father-son bonding and your videos kept this SUV running. So THANK YOU, Timmy The Tool man. I am not sure if this is the right place to ask you the following: My SUV is a 1998 4WD 4Runner limited (3.4L). The Oil Cooler is leaking, but I cannot find any videos or instructions on how to reach it (It's almost impossible to reach it on a 4WD). All videos reference a 2WD. Do you have instructions for removing the oil cooler on a 4WD in your maintenance manual, or can you point me to a video? Your help is greatly appreciated.

[@TimmyTheToolman]

You know, I wish I would have filmed it when I helped my buddy replace his oil cooler seal but we didn't. You would first want to remove the alternator to get it out of the way. Next, you want to jack up the rig on the driver side and remove the wheel. Next, remove the rubber mud flaps out of the fender well. This will give you a good view of the oil cooler. It's tight to get in there but you'll have enough room to do what you need to do. I'm guessing you're talking about an oil leak but maybe you're talking about a coolant leak. If it's just an oil leak at the connection of the cooler to the block, you have to disconnect the two hoses that attach to it and then break free the bolt that holds it to the block. You'll most likely have to give the cooler a tap with a plastic mallet to break it free. Once off, you pick out the old o-ring gasket. It can be a pain to remove but some small metal pick tools will help you get out fully out. Start watching this video at 9 minutes and 9 seconds to see how to remove the oil cooler: kzbin.info/www/bejne/d6erp55vg5KbiqM Start watching this video at 30 minutes and 31 seconds to see the installation of the oil cooler: kzbin.info/www/bejne/lXjCq6R6eJ6efK8 You'll not only want the oil cooler o-ring gasket but you'll also want to replace the oil cooler bolt washer. Good luck! If you have more questions, just ask.

[@cafesami9356]

@@TimmyTheToolman Yes, it is the Oil Cooler and, Thank you very much for these hints. I purchased the rings last year from Toyota, maybe I will make an attempt to change them this coming weekend. This past weekend, I spent it with my son changing his breaks and rotors : ). Thanks again, you are the best.

[@TimmyTheToolman]

@@cafesami9356 No problem. Good luck with the job. Remember to have some coolant concentrate and distilled water on hand to top off the cooling system when you're done. Those Lisle spill free funnels work good for burping the cooling system. Try to put the rig at a slant with the front end higher than the rear. Turn the heat controls of your front and rear(if you have one) heaters to full hot so any air pockets get pushed out of the heater core and heater core hoses. You won't lose a ton of coolant but you'll want to top off the system and properly burp it. Happy Wrenching!

[@cafesami9356]

@@TimmyTheToolman Thank you, Timmy. I have both the Toyota concentrate and the Lisle funnels (I watched your video on flushing the radiator). If I am not mistaken, I believe I watched every video you made for the 4Runner. : ) We need more of you for other cars. You are the best.

[@TimmyTheToolman]

@@cafesami9356 Thanks for being a fan of our channel. We appreciate it!

[@conor1956]

This may be a really dumb question, but how are you tracking your trans temp on the 98’? I thought the scan gauge II couldn’t read it for the 96-98? Awesome video as always!

[@TimmyTheToolman]

I'm tracking it via an aftermarket gauge I installed. Check out the video. kzbin.info/www/bejne/nIXCY6awmbCLiK8

[@conor1956]

Awesome, thanks! I missed that one I’ll check it out now!

[@TimmyTheToolman]

@@conor1956 You're welcome. Hope you enjoy it!

[@rthomas2157]

Hi Tim. Looking at doing this mod here in the near future. Just had a quick question for you did you choose to go with the Hayden 699 just because it is larger/more cooling capacity and it has the bypass? I’ve seen others use the Hayden 678.

[@TimmyTheToolman]

Yes, I chose it for its size and bypass capability.

[@rthomas2157]

Thanks Tim

[@TimmyTheToolman]

@@rthomas2157 You're welcome.

[@1stgenoffroad]

Hey Timmy! Good video. What temperature gauge did you use?

[@TimmyTheToolman]

I used a Max Tow gauge. The install is documented in this video: kzbin.info/www/bejne/nIXCY6awmbCLiK8. All the parts used for the install are linked in the video description. Glad you like the video.

[@1stgenoffroad]

@@TimmyTheToolman Thanks for the reply. Now that it's summer, how is this external doing to keep the trans oil temp in check? I've installed an aluminum external trans cooler in my 1996. Haven't driven it yet. I'm wondering if a cooler fan is necessary or even possible.

[@TimmyTheToolman]

@@1stgenoffroad The temps are doing well but I still need to employ all the tricks I know like turning overdrive off when appropriate and using 4Lo when climbing sustained grades while 4wheeling. External coolers help keep your temps down but you still need to drive smart and even pull over sometimes to let your trans and engine cool down when appropriate. The more aftermarket things you put on your rig like bumpers, skid plates, roof racks, etc the heavier your rig gets and thus increases the strain on your transmission and engine. Some people use an accessory pusher fan but I believe this only helps during slow moving situations, like 4wheeling, when there isn't significant air being pushed through the front grill. When you're not running the fan, the fan attached to the front of the cooler will actually hinder air flow through the cooling fins of the cooler, so that's something to think about.

[@1stgenoffroad]

@@TimmyTheToolman Thanks for the reply. I'll just have to keep an eye on it for now.

[@TimmyTheToolman]

@@1stgenoffroad No problem.

[@cordel666giglesworth6]

Did this install ran 2 trans coolers in series keeps everything cool

[@TimmyTheToolman]

That's one way to do it. Good job.

[@cordel666giglesworth6]

@@TimmyTheToolman your videos helped me a ton thank you sir for all the info you shared

[@MrCalifornia1234]

I was going to install this on my first gen tundra but then realized it comes stock with one.

[@TimmyTheToolman]

Yep, some of the Toyota models came stock with an external trans cooler. Nice bonus.

[@drummer781]

i always hear about people getting stuck at BFE? Is this a popular offroad trail?

[@TimmyTheToolman]

It stands for Bum F*ck Egypt. It's an old saying meaning you're stuck out in the middle of nowhere far away from help. www.urbandictionary.com/define.php?term=bum%20fuck%20egypt

[@williamanddonnaevans]

Timmy, I’m not sure I’m seeing it right on your video, but it appears that your return cooling line is tight against your lower radiator hose. If that’s the case then sooner or later you’re radiator hose is going to fail.

[@TimmyTheToolman]

I'm going to take another look at it. Thanks for the observation.

[@julioarrecis666]

hi Timmy, quick question, I'm planning to overland my sr5 i already order my rear bumper, i already have the front one with a x-bull 13500 , do you think should i go with the hayden 699 or the 678? thanks again.

[@TimmyTheToolman]

The 699 has a thermal bypass for cooler conditions. How well it works? it's debatable. But, I'd probably still go with the 699.

[@julioarrecis666]

@@TimmyTheToolman thank you so much.

[@TimmyTheToolman]

@@julioarrecis666 No problem.

[@danielkay2925]

Forgive my noob question but I just recently picked up 3rd gen 99 4unner my plan is to use the vehicle for 20% overland/off-road and 80% daily. I am going to get the cooler done for my transmission but I want to know if the reader/temp gauge will be necessary and will running full synthetic atf be necessary for what I plan to use the vehicle for?

[@TimmyTheToolman]

OEM trans fluid or a Dex III / Mercon /mercon V compatible fluid is fine. Synthetic is good and is pretty common now. 99-2002 have a built in temp gauge to read trans temp from the ECU. So you wouldn’t need to install a separate gauge, just hook up an OBDII reader with an app or get a scangauge II and program in the trans temp code. - Sean

[@danielkay2925]

Thank you! Also one more if my friend were to do this to his 98 where do we get the “T” fitting and the sensor?

[@i-b1982]

I have a 98 4Runner and just got my Hayden 699 mounted up but need to get some 3/8 line. You show two 3’ sections needed, is that enough? Seems kinda a little far for only 3’?

[@TimmyTheToolman]

6 feel is enough for the way I routed it. If you choose a different path for the hoses and come around the passenger side of the radiator, you'll need more hose.

[@i-b1982]

@@TimmyTheToolman thanks for the reply, I’ll get 7’ just in case :) you rock thanks for what you so

[@TimmyTheToolman]

@@i-b1982 You're welcome. Good luck with the install.

[@edwinalexander1170]

How can you say about Hyden 526 is it effective ?????

[@TimmyTheToolman]

I have no experience with that cooler and fan setup, but I'm sure it would work fine.

[@zenjon7892]

Hey Timmy, is it possible to do a steering wheel mod? I saw one in a 2002 4Runner and I like it more than what I have in my '97 rig, but I don't know if it will fit/work or not

[@TimmyTheToolman]

That “mod” would require you to splice in a 98+ airbag connector OR swap the clock spring.. the steering wheel itself secures to the shaft the same way throughout all 3rd gen years (96-2002) It is held on but a 19mm nut.

[@zenjon7892]

@@TimmyTheToolman I think I would go the "splicing" route. Thanks, Timmy

[@TimmyTheToolman]

@@zenjon7892 we have some extra 98+ airbag connectors if you need one

[@zenjon7892]

@@TimmyTheToolman ok, I'll take one

[@TimmyTheToolman]

@@zenjon7892 email Sean at: [e-mail]

[@elad3569]

Can you pls send a link for the inline filter?

[@TimmyTheToolman]

*Magnefine 3/8" Magnetic In-line Transmission Filter amzn.to/35p6heN

[@mitchellpeterson2883]

This is probably a dumb question. If I have an ultra gauge that monitors transmission temps and I do this and bypass the stock cooler, will it still read the temperature correctly? I'm not really sure where the thermometer for the transmission is. I have a 2000 2wd 4runner. Thank you.

[@TimmyTheToolman]

Yes, you'll still be able to read the trans temp correctly.

[@mitchellpeterson2883]

@@TimmyTheToolman Appreciate it!

[@TimmyTheToolman]

@@mitchellpeterson2883 No problem.

[@KaskadeHD]

I’ve heard running the cooler in line with the radiator is better if you are doing a lot of stop and go traffic in hot weather due to the transmission cooler only being able to cool when air is blowing through aka moving at speed . And if the radiator is replaced when it needs to and you maintain your coolant system properly there shouldn’t be any worries of a pink milkshake. Thoughts on this?

[@TimmyTheToolman]

Well, what about your engine overheating when you're not moving? That's what the fan is for. It not only pulls air through the cooling fins of the radiator but it also pulls air through the AC condenser and any coolers in front of the radiator. You made the same arguments I've made in the past about limiting the chances for the pink milkshake by just renewing the radiator and keeping the coolant in good shape. I agree. But, there's no guarantees in life. The trans cooler could still fail if you do everything right. Would you lessen those chances by keeping the cooling system in good shape? Of course you would.

[@KaskadeHD]

@@TimmyTheToolman Hey I just want to say how awesome it is that every video I leave a comment, you respond with a detailed message. EVERY time. It's mind blowing you have time and put the effort to do that. You're an essential part of many people's lives when it comes to wrenching on these vehicles and put out quality and detailed videos. Keep up the kick ass work man. Thank you.

[@TimmyTheToolman]

@@KaskadeHD Thanks a lot for recognizing our efforts to answer people's questions and acknowledging their comments. It can be pretty time consuming but I think it's a nice thing we can do for people since our channel isn't so big that we can't keep up with it. We appreciate the kind words. You're very welcome and Happy Wrenching!

[@KaskadeHD]

@@TimmyTheToolman Question. So I just installed the Hayden 699 transmission cooler on my 1998 4runner. Install was straight forward. But after the install, when I drive the 4runner forward (doesn't happen in reverse that I've noticed) it makes somewhat of a whining or whirring noise. I jacked up the rear wheels and put it in drive so I could hear where exactly it's coming from but when the rear wheels aren't under load it doesn't make the sound. Only when driving forward.. any ideas? Could it be causing damage? I haven't driven it since. Edit: I just took another look at my work. It looks like I actually ran the send line to the TOP, and the return line from the bottom of the cooler to the return hard line.. Would you think this would cause the noise? I did read the 699 was 'bi-directional flow'. I should also mention the 4Runner was defiantly not up to temp each time I started it and heard the noise. It ran for a total of 2 minutes max. On a cold start it makes the noise, I never gave it enough time to warm up to open the cooler..

[@TimmyTheToolman]

@@KaskadeHD Did you confirm your fluid level was good after the install? Sounds like it might be an issue with the torque converter. I don't know how installing the cooler could cause that unless it's an issue with the fluid level. Did you run the cooler in-series or stand-alone? Any chance the lines you ran are kinked?

[@tahahadada1936]

Hello Timmy ,is it possible to install Jeep wj seats on a 3rd gen 4 runner

[@TimmyTheToolman]

I'm sure it's possible but I doubt it would be plug and play. You would have to make some alterations so you could bolt it to the body. I doubt the mounting holes would be the same.

[@tahahadada1936]

@@TimmyTheToolman legend

[@erniekropf665]

How many quarts of ATF will I need to do a full flush and refill, and why Valvoline full synthetic instead of a genuine Toyota ATF?

[@TimmyTheToolman]

The system holds around 12 quarts. I usually run around 13-14 quarts through the system to get the fluid really clean. You can use whatever ATF you want. As long as what you use is compatible with the spec suggested by the manufacturer, you're good to go.

[@erniekropf665]

@@TimmyTheToolman, ok thank you very much. 😊

[@TimmyTheToolman]

@@erniekropf665 You're very welcome.

[@JackJack-nc5nl]

If I purchase all the parts you have listed can I pay you to do the install?

[@TimmyTheToolman]

Sorry Jack, we're not mechanics for hire. We make videos to help people.

[@thepianofamily8304]

I live in TX and the day time ambient temperature can go to 100+ degree F. I did what Tim did (bypass the radiator) and installed Hayden 699. Scangauge ii reported temperature around 190 degree F during the day and 165 degree F during the evening (ambient 86 degree F). Is this normal? Should I or can I install another smaller Hayden in tandem to better cool the ATF?

[@TimmyTheToolman]

Those temps seem high. Is that around the town driving on relatively flat roadways? I don't average that high of temps with my Hayden 699 cooler and I'm driving in similar ambient temps. If I'm driving in the hills, then yes, the temp goes up and then you need to utilize tricks like turning off overdrive to keep the temps down. What are your engine temps like?

[@thepianofamily8304]

@@TimmyTheToolman It is when driving on flat roadways. My rig is 2000 4x4 but I don't do trailer or off-roading. Can I install a 2nd smaller Hayden or hook it in series with the radiator? Thoughts?

[@TimmyTheToolman]

@@thepianofamily8304 Yes, you could run two external coolers in series. Guys have done it.

[@thepianofamily8304]

@@TimmyTheToolman Coolant temperature is consistently at 200+ deg F when driving in town, according to Scangauge 2. The TFT is ~195 deg F. The ambient was 103 deg F. I have ordered a 2nd 699.

[@TimmyTheToolman]

@@thepianofamily8304 Have you checked the function of your fan clutch yet. That might be part of the problem.

[@Respecet1981]

In Kuwait, temperatures in the summer reach 50 degrees Celsius. Is there any advice from you regarding the transmission cooler for this weather with the fj car, knowing that the Fj cars in Kuwait have a horsepower of 268 and a torque of 380 Newton, because in our country this car is still sold from The dealers and yes that Toyota modified the engine from 2017

[@TimmyTheToolman]

The only advice I could give is install the biggest external cooler you can and maybe add an accessory electric fan(s) to push more air through the cooling fins when traveling at slower speeds.

[@Respecet1981]

@@TimmyTheToolman you just read my mind im thinking of this step Thanks a lot brother with best wishes

[@TimmyTheToolman]

@@Respecet1981 No problem. Hope it works out to keep your trans temps down.

[@Respecet1981]

@@TimmyTheToolman sure brother 👍🏻

[@Respecet1981]

@@TimmyTheToolman the biggest trans cooler can fit the fj is the 30 btu tru cool max the long one I went to the auto cooling technicians and they told me this is the biggest transmission cooler you can install in your car and I spoke with one person have the 2020 fj and he told me it work very nice, the trans temp is stable I will try it sorry if I disturbed you

[@hermanq5615]

Use socket head screws instead of hex heads and you won't need to dremel your brand new oil cooler and make it look worse.

[@TimmyTheToolman]

Thanks for the tip. I'm ok with the Dremel work though. It's just looks for something nobody other than me will ever see. I'm a function over for kind of guy. It doesn't have to be pretty but I definitely want it to work.

[@michaela2079]

Sorry, if this has already been asked, but when I went to purchase the 699 Hayden Trans Cooler, it says this cooler is not compatible with my vehicle and advises me to purchase the 696 Hayden Trans Cooler. I just wanted to make sure. Thank you.

[@TimmyTheToolman]

You can make any cooler compatible if you want. A cooler is a very simple device and isn't really vehicle specific. As long as you can securely mount it, it will work.

[@michaela2079]

@@TimmyTheToolman Thank you TImmy!

[@TimmyTheToolman]

@@michaela2079 No problem.

[@genxiong2695]

Hey Tim , installed the same cooler. My oil temp was around 175ish . After the install I’m getting 89. This is with the AC on. Is this normal? Seems too low.

[@TimmyTheToolman]

That seems low. I see low temps in the morning when it's cool and I just started driving, but it will climb into the low 100's until I start climbing hills and then it will rise into the mid 100's. What kind of ambient temps do you have where you live?

[@genxiong2695]

@@TimmyTheToolman You know what Tim. I went back on my notes and it was actually 155 instead of 89. Sorry. So that is like 11%ish drop. Not too bad. I was doing multiple tests on other things installed and lost track. But to your point, I should test going up a steep incline/mountain pass. Without the cooler I was averaging 220-230ish. This incline is in the 15-25 degrees grade. BTW I live in the central valley where it gets really hot! So very similar weather to what you encounter. 🙃 Thanks for replying!!

[@TimmyTheToolman]

@@genxiong2695 Gotcha. Let me know how the testing goes for you.

[@genxiong2695]

@@TimmyTheToolman Will do. Thank you for making these videos and helping out all the DIY weekend warriors!

[@TimmyTheToolman]

@@genxiong2695 No problem Bro. It's our pleasure to help the Toyota Community out.

[@vanliferr4079]

So should I return my bm cooler? I'm bypassing but my truck is stock and mostly daily driving

[@TimmyTheToolman]

I'm curious, was this video a suggested video at the end of one of our other videos? The reason why I ask is this video is unlisted. I'm trying to figure out how you got the link to watch it in the first place.

[@vanliferr4079]

@@TimmyTheToolman I was searching on your playlist for Tacoma 1 st gen videos and this video was in the playlist. Right at the very bottom

[@TimmyTheToolman]

@@vanliferr4079 Awe, interesting. Thanks for letting us know. OK, to answer your question, the B&M cooler might be sufficient but it depends on how you're going to use the rig. If you plan on doing a lot of mountain driving, and especially when there's hot ambient temps, like in the high deserts, the B&M cooler might not be enough. If you're going to do mostly mellow flat land driving, the B&M cooler should suffice. But, if you're not currently monitoring your trans temp, I highly recommend that you start so you're not guessing how well that cooler is doing for your trans.

[@vanliferr4079]

I am unable with my driving to get my tans temp even up to 175 with the current weather using the BM 2604 so far, I have this cooler in the garage if summer changes this tho.

[@TimmyTheToolman]

@@vanliferr4079 Your experience is common. Easy daily driving isn't going to raise your temps that high. As long as you can get the temp up to 150 degrees, moisture won't accumulate in the trans. The ambient temps definitely affect your trans temp. Temps really rise when you drive in the mountains.

[@seandalejackson2525]

Wouldnt you want that filter before the cooler so it doesn't get clogged?!

[@TimmyTheToolman]

Well, if your trans is sending particles big enough to clog the cooling channels, you have some problems. There's very small passages in the valve body as well.

[@mikekmalick]

I own a 2001 Tundra 4x4 limited 4.7 liter. How much better is this cooler then my stock one and do I really need this transmission cooler?? I don't see a temperature gauge for my transmission anywhere.

[@TimmyTheToolman]

The Hayden 699 is going to have quite a bit higher cooling capacity than your stock one. I've seen the size of the stock ones and they're not that big. You don't have a trans temp gauge. All you'll have is the "Idiot Light" that will light up on the dash if you overheat your trans, around 300 degrees. If you want to monitor your trans temps, you have a couple options. There's OBD II port bluetooth readers that can send information to phone apps like Torque Pro. Torque Pro is for Android phones only though. For iPhone, there's other apps you can use. You also have to make sure you get a reader that works with your platform, Android or iPhone. The other option is getting a scan gauge or ultra gauge. I use to use the phone app but decided to go to a scan gauge so my phone didn't have to bounce back and forth with different screens like when I'm using my phone for navigation at the same time. If you open the video description by clicking on "Show More" and you go to the "Helpful Tools" section, you'll find a link to the Scan Gauge tool I use in my rigs. So, it depends on how you drive your rig and the temps you're seeing whether or not you need to upgrade your trans cooler. If you drive mostly flat roadways, you probably don't need to change anything. If you drive a lot in the mountains or tow, you might find the stock trans coolers aren't doing enough to keep your trans temps down.

[@mikekmalick]

@@TimmyTheToolman I driver in the Eastern High Sierras for about a month per year towing a small fishing boat.

[@TimmyTheToolman]

@@mikekmalick You should start monitoring your trans temp then. Ignorance isn't bliss in this situation. Knowing what your trans temps is doing will let you know when it's prudent to pull over and give your trans a break. I'll pull off the roadway when my trans hits around 230 degrees and I know I'll still be climbing further. The same goes for the engine temp. That analog coolant temp needle gauge is pretty much worthless. Once you see the needle start to rise higher than normal, your engine temp has already spiked. It's better to know the actual digital temp your engine is at to catch an issue quicker. 210 degrees is the engine temp I start to get worried and will either pull off the side of the road to let it cool down or I crank the heater full blast and suffer in the cab to help drop the engine temp.

[@mikekmalick]

@@TimmyTheToolman should I install a aftermarket transmission temp sensor gauge?

[@TimmyTheToolman]

@@mikekmalick That would be the harder way to go Mike. I gave you two options of how you could read the trans temp which wouldn't require you to have to install an aftermarket gauge. Installing a gauge would be much more work.

[@connorm1600]

Previously you ran it through the radiator cooler but now you’re not what is your logic behind that?

[@TimmyTheToolman]

The main reason that people bypass the stock cooler is to eliminate a trans cooler failure in the radiator. The coolant and ATF mix and that contaminated mixture gets back to the transmission and kills it. I still think radiator cooler failures aren't all the common, but there is a chance because I've heard of it happening to plenty of guys via Toyota forums and Toyota Enthusiast Facebook pages. The radiator I installed in my 2000 4runner when I made that video years ago looked like an identical OEM one. Fast forward a few years when I bought my 98 4runner and I wasn't able to buy the same quality radiator from Toyota. It was clearly built cheaper and the price reflected it. The cost dropped from $200 to $100. So, the cheaper built radiator has me questioning if I'm now more at risk of a trans cooler failure. For my 2000 4runner, I'm still running my external cooler in-series with radiator cooler. This is an experiment for me and I'll know this summer after doing some trips if I like what I see or I decide to go back to running the cooler in-series. I'll give updates via a pinned comment how my trans temp do this year and share my decision to keep running it bypassed or to go back to running it in-series.

[@josecastro2630]

Will this work on a 2002

[@TimmyTheToolman]

Yes.

[@genxiong2695]

What's the difference between the 699 and 678 rapid cool? Amazon have the 678 compatible with 3rd gen 4runners but not the 699? Thanks

[@TimmyTheToolman]

The 699 has the thermal bypass. Ebay sells the 699. We provide a link in the video description.

[@genxiong2695]

@@TimmyTheToolman Got it. I bought mine from Amazon. Just a few dollars more.

[@abrahamhorball1143]

Hello Timmy what kind of cooler is that 699 or 679 or 698?? Hayden??

[@TimmyTheToolman]

There's a much quicker way you could have found your answer. #1, you could have simply read the first sentence of the video description. #2, you could have watched the first 1 minute of 40 seconds of the video. Abraham, you're going to have to try a little harder than this. I like answering everyone's questions, but I was tempted to ignore this one.

[@abrahamhorball1143]

@@TimmyTheToolman thanks a lot I totally miss that one, I’m sorry about that, I just can’t find the 699 on Amazon only the 698 do you think there is a big difference between those two? Thanks again

[@TimmyTheToolman]

@@abrahamhorball1143 I provided a link in the video description. I got mine from Ebay.

[@abrahamhorball1143]

@@TimmyTheToolman hey I just find one for 75 dollars thanks !!!

[@TimmyTheToolman]

@@abrahamhorball1143 No problem

[@bluesky-ud9wg]

So you bypassed the Factory Cooler all together?

[@TimmyTheToolman]

Yes, I'm trying it out and I'll see how the trans temps do over time and make a decision to keep it as is or change it to run the external cooler in-series with stock cooler in the radiator.

[@bluesky-ud9wg]

@@TimmyTheToolman Well I'm a Toyota MDT and here is how I've installed my coolers & filters; Leave the Trans, go into the installed cooler, back into the radiator, into the filter and back to the trans. I've installed Remote Oil filter mounts on all my Toyotas, (3) and use the Purolator Pure One filter, changed once a year along with flushes every 30,000. The reason you want to go into the installed cooler first then back in to the radiator is because it stabilized the temp. Kinda like this; Too hot fluid leaves trans, tires into the installed cooler, cools the fluid too much but then brings it back up to operating temp in the radiator and back to the trans.. The temp should be between 140-170. It should never get past 180, that's the temp that starts oxidizing the fluid and hardens seals, generally not good past 180. Oh and use Synthetic Trans Fluid PERIOD. I welcome you're comments on this, thx

[@genxiong2695]

@@bluesky-ud9wg So basically, you recommend series?

[@bluesky-ud9wg]

@@genxiong2695 I'm a Toyota MDT, I do recommend running into the After Market cooler first then back into the Radiator cooler to stabilize the temp

[@genxiong2695]

@@bluesky-ud9wg Ok. So you're not answering my questions correctly or you are unsure. There's 2 ways to run the cooler. One method is in series, meaning you are not bypassing the radiator but instead using the cooler in conjunction with it (which is what Toyota run on stock coolers). The other method is bypass which you run straight into the aftermarket unit and into your transmission. The radiator will no longer cool the transmission fluid but instead, the cooler will. Make sense? Here's the in-series method: kzbin.info/www/bejne/aHbXgn2YaLd3sLs

[@stco2426]

Another good, recent transmission cooler vid is here: kzbin.info/www/bejne/gWamma2HmqZ7l80 with lots of similar advice. Not seen the additional trans filters before. Will look at similar for other uses. Like the replacement hook-up. Gr8 vid

[@TimmyTheToolman]

I like Eric the Car Guy. The in-line magnetic trans filters are definitely a nice addition. I've been using them for years on my rigs. Glad you like the video.

[@brycethoreson9216]

How much tranny fluid did you add

[@TimmyTheToolman]

Very little, between 1/4-1/2 quart. Add a little at a time and recheck the level until you get it right.

[@jonnytacooutdoors]

Anyone use a Long Tru Cool??

[@TimmyTheToolman]

Never tried it. The larger the cooler, the more cooling capacity. But, there can be issues running too big of a cooler. Even with the thermal bypass, more cooling does happen and it could keep your trans temp abnormally cool in cold climate conditions, like when you drive to the snow to go skiing.

[@jonnytacooutdoors]

@@TimmyTheToolman hey great videoN these Toyota’s transmission I’ve been reading like to run hot! Highest temp I’ve seen is 208 going up a steep pass after about a 45 minute drive. Temp dropped back down after going back to flat. I have a lot of additional weight from the parts I’ve added to the truck. I’m thinking a better trans cooler would help out. Unless that’s not super hot. I just feel like anything over 200 isn’t good for fluid life. 😁

[@TimmyTheToolman]

@@jonnytacooutdoors 208 Is not that bad. If you maintained 208 for a long time, then that wouldn't be great. 230 is the temp I start to be concerned at. It's ok for the trans fluid temp to spike for a short period. That's totally normal. However, you wouldn't want to see super high temps, like 240+ even for a short while because that's not good. If I'm driving up a long steep grade where turning overdrive off isn't helping (speed below 40-45 mph) and my trans temp gets up to 230, I'll pull over keeping the engine running and I'll raise the engine rpms to spin the fan faster so more air is pulled through the cooling fins of the trans cooler and radiator to expedite the cooling of my engine coolant and trans fluid. Once the temp drops down well below 200 again, like around 180, I'll continue the drive up the grade. The whole reason to monitor your temps is to let you know when it's prudent to pull over and give your rig a break and to also alert you there's an issue, like a coolant or trans fluid leak.

[@jonnytacooutdoors]

@@TimmyTheToolman great info! Thanks! We driving Ca to Or this weekend let’s see if I get above 208, I feel like I will. 35’s and a lot of extra weight. 😁🌮✌🏼 thanks again for the info.

[@TimmyTheToolman]

@@jonnytacooutdoors If you drive up a steep slow road, you'll easily go above 208. If you're able to maintain speeds of 45+ mph, turning overdrive off locks up the torque converter and will keep your trans temps down. Have you re-geared yet? I"m guessing you probably have with 35's.