Highest allowable transmission temp. Cummins.

[@johniedavis9150]

People alway call me weird for warming my truck up every time before I go anywhere, let it cool off till all temps are within normal ranges and keep the heat out of engine and transmission much as possible! I watch my temps like a hawk! I made it almost 10 years, 168334 miles on a stock 68rfe before the input shaft broke when I hit a pot hole pulling snoqualmie pass. ended up on exit 53 off ramp headed east. Was 3 years old when I bought it, had 48k miles. Just got it rebuilt with upgrades and she’s on the road again!

[@DavidBrown-jt7yi]

This is a great video. I just got off the road after 8 hours and watched the temps on the 1 ton all the time. Aisin was between 163 and 165 the entire time. The oil temp ranged from 190 to 203 and this is empty. I’ll check if temps increase when I hook up the 10k RV in a few days. Thank you for the information.

[@alanb.4660]

Engine oil temp on the new trucks are estimated by the computer, not a real temp

[@Jay_Force_One]

I’m a Heavy Equipment/Diesel Mechanic in the Air Force. I don’t know man, 185F is a pretty standard operating temperature for most transmissions. Anything between 170F-200F is pretty normal and safe. Most Manufacturers set the limit of 220-230 for maximum safe operating temperature. You won’t even get a message or light until those. For cooling, high temperatures don’t always mean cooling problems. The radiator and fans can only cool the fluid so much. There is a max temperature that your fluid is going to reach under the conditions it’s being subject too (Ambient Temp, Load, etc), and all the radiator is doing is cooling it a few degrees so that it can return to the system to absorb heat energy until it reaches its max temperature again. Essentially, if the temperature is staying relatively the same, it’s doing its job. You know you will have a cooling problem is those temperatures continue to rise. If you’re at 215 and it’s steadily going up….that’s when you have a cooling problem and should stop.

[@hardtruth2039]

On my 2018 Ram 2500 I added a deep trans pan that added 6 quarts of fluid and i removed the thermostatic cooling block. I live on the gulf coast and my trans runs mainly 135 to 150 max. I don’t tow heavy.

[@ck3561]

How many miles do you have and how often you changing fluid now with those low temperatures

[@stracer71]

That is the best thing you could have done for your transmission. That’s the first upgrade I recommend to my customers.

[@robstewart5995]

My 2021 3500 6.7 standard output 68RFE got up to 210 briefly pulling an 18,000 lb 5th wheel in the Rocky Mountains on an 8% grade. This reading was in the center of the transmission temperature gauge between cold and hot. Usually runs 160 to 190 in normal towing. Changing fluid and filters at 60,000

[@tedbaxter5234]

That was a fine dissertation. I am new to diesels, took 14.6k from Denver to Atlanta. I installed a monitor before I left. It was fascinating to watch the interplay of temperatures - I was worried more than once - mostly because I had no experience to rely on. Again, great video, thanks a million!

[@danny.b]

Very useful info as usual Paul ! Thank you

[@yerwrng]

Temps 100 above ambient are common according to the transmisson engineer that visits the Cummins forum website. 185 was said to be a no issue operating temp . I see 175-205 all the time loaded in stop and go especially in the mountains. I do have 35s on stock gears but I have a huge aftermarket cooler and always shift manually to keep it in lower gear to keep it where it should be rpm wise and the trans converter locked as much as possible. We'll see if the new 4.30 nitro gears change the temps at all pulling in stop and go . I did 4.30 because I probably will do a 37 next tires bit if not 4.30 gives good gearing with both tire size. I'm only grossing 18.5-20k combined its not like im pulling a 20k trailer behind me woth a combined gross of 30k .

[@PaulHigginbothamSr]

If I would have known this I would have pulled over and waited because I ran 240 for an hour. I am going to check the fluid and if burnt I will change it.

[@mikestrucks]

Good video Paul ! I always delete my transmission thermostat. It helps a lot with temps. I also use in the summertime a 160f thermostat in my engine.

[@nathanurick8320]

Please don’t stop making these videos.

[@holybuba]

Thank you thank you thank you. I have sheared this video with 10 guys. I am always insisting that every watches the temperature and let's these trucks cool down

[@PeeterPuncher]

I used to work in big name powertrain testing lab running numerous engine and transmissions. 150-180F and if it gets to 200 better let it cool. The key is keeping the converter locked. An unlocked converter creates most of the heat in the transmission.

[@jordanhumphrey9615]

I've always heard 220 or higher pull over transmission fluid cook point is rate around 220

[@cowboyjohnnydriver9795]

Good video I was mad today in GA in traffic on a US highway with only 7k only on the trailer stop lights got to 191 degrees seen before climbing a mountain with 20k understood but 21 ram 130k was worried been services and was wounding what the f#%& not a good feeling

[@aoleson]

The 6.7 powerstroke thermostat for the trans don't even open till 195. My 2016 runs between 195 and 210 no matter what. Don't matter if I'm empty or pulling my 21k 5ther it hangs right there flat or up grades

[@KCInferno]

Thermostat? Lol don’t have one. I had it removed. All transmission fluid goes to the cooler. I run 60 degrees above ambient not pulling. I run 70 degrees above ambient when pulling 16k pounds. Max transmission temperature is 200 just like you said. Without the thermostat I see 170 max when pulling. Yes I pull across veil and grapevine passes. If I lived someplace cold or pulled to cold areas I would run a thermostat, but I follow the warmer weather.

[@thepeeve]

My ‘21 cruises at 165 with an 11k weight of an empty gooseneck. MAYBE will get to 167 when loaded lol I have had it spike more than I’m comfortable on those back roads in the hills but haven’t had issues. I didn’t think of doing 4L to keep the temps low in the trans but make sense

[@bryonsusedautos]

The optimal temperature range for transmission fluid is 175 to 220 degrees!

[@joshpodolsky7740]

Not for an aisin.

[@pogojp]

This is only for Allison trans. Normal trans temp is 175-210. Not for all trans though.

[@jorgealdana8039]

I have a 2022 Cummis truck, it has 54k miles, at 34k miles the transmission temperature began to rise to 231 degrees, the dealer said they put in a new transmission and that temperature is Normal. I have a new transmission and the problem remains the same, I have no experience in this type of truck, can anyone guide me, I would appreciate it.

[@ivopsilva]

I have a 22 Ram 3500 cummins. I pull a 3 car trailer. When empty usually it ranges between 168-176. When loaded 176-200. Sometimes it goes up to about 210. I get nervous when it happens lol

[@bryonsusedautos]

@@jorgealdana8039 need to replace the 68RFE Thermostatic Bypass

[@jasonhenry1690]

Appreciate the videos Paul as always. If you could post a video on how to access the radiator and condensor on a 2019 in order to wash it out when its plugged would be awesome. Thanks again bud!

[@tonyphilbrook8650]

Beautiful country, great ride along

[@caroldavid1019]

2016 3500 Dually, 68RFE, with the OEM trans bypass value runs between 172 and 178, summer & winter, empty or pulling 15K up a mountain. I installed an ATS bypass and runs between 172 and 178 when towing no matter the outside temp.

[@hotshotstuff8080]

Thanks for another great Ram video! I’m a one truck business and really appreciate you sharing your expertise and knowledge!!! My 2020 Ram 3500 is coming up in 150k. I deliver RV’s with it so typical load is around 11-15k fifth wheel campers. My coolant is rated for 150k or 5 years I believe, at what point miles wise do you change coolant and do you do a flush on the system? Also what products or procedure do you do to clean the radiator on the outside? Thanks again Gods speed!

[@brenteason9891]

217F is right at normal operating temp for a Powerstroke 10 speed transmission. Even my crappy 68RFE doesn’t run that hot towing heavier loads.

[@bryonsusedautos]

Yeah the ford run real hot!

[@jonathonsmith7694]

Fords Transmissions run whatever the coolant temp is. Want it lower, lower the t stat

[@czwarlord9243]

So does the Allison. My 6 speed Allison was 190-210s on average towing. Slow high altitude hill climb it was quite normal to see 210s or higher. Highest I ever seen was 245 and no warning light. Needless to say I pulled over and let it cool

[@markvolker1145]

we run Cat and allison trans in our frack pumps.. 200* is where they typically run. If we are slipping the trans and not in lockup we may see 230* for brief moments and we get 10000-15000 hours out of them

[@robertmatthews2776]

LOVE This, GREAT.. GOD BLESS YOU...

[@myname7118]

I pull about 17k with my aisin truck pretty regularly. It's yet to see 190 on the trans temp. My old 48RE truck ran 200-205 with zero load. It saw 220 about once a week and 235 a couple times. That's even after it was rebuilt by a reputable builder.

[@myname7118]

@B B Anything is possible, but it was like that before the rebuild too. Zero parts in common. Not even the case.

[@Formerlywarmer]

My 15 3500 with 68 re runs 168 empty or 168-9 towing about 10k race trk trailer and track stuff. I never seen it go over 169. Hills or in the flats running 80 on flat roads has yet to get hot. Deleted and tuned at about 120k miles after def fault and it’s at about 155k now. MOPAR2YA

[@bigd8812]

Have a 2018 3500 should I get worried that its going up to 190 from the normal 165 after5 hours of towing 23000?

[@myname7118]

@@bigd8812 190 wouldn't bother me at all. Over 220 is where you want to start worrying.

[@redbarron6574]

Mine runs at 168 F. Towing 14,500 lbs. 68RFE. 2020 long bed 3500. This weekend it went to 170 or 172 for a few seconds and then right back down to 168. That’s exactly what my 2018 with the HO did with Aisin and the same fifth wheel. If I put the truck manually in 5th gear all the temps come down.

[@patc5116]

Which transmission do you prefer?

[@redbarron6574]

@@patc5116 well that’s really a great question. I do like the 68Rfe better. I got the SO Cummins on purpose, I will never tow more than 14,500 lbs. I like the extra payload, plus the 3.73 rear end versus 3.42 is much more responsive. This tranny is also staying exactly the same 168 degree temp just like my Aisin. If I was towing over 17,000 lbs, I would have bought the Aisin.

[@ericestep9880]

I got a 68rfe here. Pulling hills on a 90 degree day highest I’ve saw is 170

[@sandslinger6720]

Ive gotten to 190 on my 2015 68RFE and will be installing a thermal bypass before upgrading trailers next year. Going from 10k bumper pull to a 18k 5th wheel.

[@ericestep9880]

@ I have a 2011 didn’t come with a thermostat in the lines

[@IBSC2000]

Thank you for the video

[@doneB830]

A guide is start backing if you go more than 122F above your ambient temperatures.

[@ViVA-MEXICO-AMLO]

On 6.7 cummins my clutch fan went out towing lil under 20k trailer Coolant temp 219F Oil temp 220F Trans temp 226F Drove like this for 30 mins pulled over and removed the grill and led bar light attached to my front bumper from restricting my air flow temps went down to normal drove six hrs. Should I replace all the fluids?? Mainly Trans and coolant??

[@Micutu_d]

I have a 2014 ram 3500 dually with a 68rfe. I haul a 2 car enclosed trailer. If temp outside is over 100 degrees my trans runs at 190 plus... 218 outside temp today keep running 200 plus. Doesn't seem to be cooling properly. New trans put in, and cooler was replaced. I have the bypass valve but not seeing the cool temps I'm suppose to. Where should I start looking.

[@joelvalentin-ww9rj]

I guess I gotten lucky I drove my Yukon with temp between 208-255 from Cali to Virginia

[@Hibbie2963]

I average 165-167 pulling 7000-20000 travel trailers. That is pulling flat, or on hills, doesn't matter. If it gets over that then yes, you got a dirty radiator. This is with the Aisin AS69RC. PS if I got over 175 I would be freaking out.

[@Workingcockers]

This week mine has started to fluctuate between 165 and 190. Could that be a dirty radiator and why. The temps climb in idle mostly.

[@jlbush8249]

My stock 2021 Cummins Engine temp runs at 186 and the trans temp is regularly in the 160's. Seems fine to me.

[@joshpodolsky7740]

Cruising down the highway 163⁰,165⁰, 167⁰ is normal I notice with aisins. Loaded or empty, but I live in the prairies so no hillclimbs for me.

[@johannaklomann2019]

Still dont get why ram doesnt include an egt gauge in these trucks, a lot of people will say oh it'll factory defuel climbing grades but that's the first thing I do with a new to me truck is put a monitor in with an egt probe usually an edge cts3. Have a 16 ram 3500 with 670k and the turbo just went out so not bad to keep an eye on everything, itll pay off in the long run.

[@SalvadorAviles408]

Cattle rancher Livermore ca I have. 2017 Cummins 68rfe I get in 4low hauling up hill 10-15 mph 4low 2 gear 170 ‘F I have a 2008 6.7 Cummins and 2017 man the 08 feels so much more at home

[@JacobOverman]

When I saw 186 I was waiting for you to say how low it was😂 my 6.7 Powerstroke runs 186-200 empty I’ve seen 244 in a hard pull up hill

[@benwarga9019]

Good video and useful information. Any progress with the Kenworth that you bought a while back, an update on the process would be cool.

[@albertbeci5643]

Thank you for the education it’s a great video. I have a Dodge ram 3500 turbo diesel 2017 how hot the coolant system should run is that normal from 190 to 197 and sometimes for a split second 200. Thank you for the explanation for the transmission you’re awesome I appreciate

[@FindingLivingston]

Get a CT2 Or CT2 install on tour A Piller. Has a Turbo Timer that will turn Motor Off when Set Time has been reaches. Also Very Important for me is Engine Load, also Gadge on CT 2 and 3. I keep my Engine Load Number below 80 (%) and I keep my EGT Temps below 1200 Degree. I would never pull a Load without the CT2 Or 3...Google it.... Best insurance for Operating. I am surprised those not using such a Device

[@betterthanideserve76]

My 2019 f250 6.7 runs just a bit cooler than the engine temps, I pull a 12k 5th wheel camper. 6% grade at 60 for 9 miles the engine gets to 231, tranny sits at 227. Per ford it's fine. Empty the trucks engine temps run 194, tranny 190. Ford says 240 is the max.

[@tylersatterfield7309]

I HAVE A 2022 3500 SRW CREW LIMITED 8FT BED 4X4 AISIN HO. WITH ONLY 16K MILES I HAVE TOWED LOTS OF VERY HEAVY LOADS NORTH OF 26000 TO 30000 40FT DUALY AXLE HYDRO DOVE TAIL WITH A BACKHOE. IT HAS STARTED TO SHUDDER DURING ACCELERATION, NOT SMOOTH. DURING UNLOADED NORMAL DRIVING IT SEEMS IT SHUDDERS DURING THE ACCELERATION, IF APPLY MORE POWER IT DOESNT SMOOTH OUT, SEEMS TO BE BEST WHEN I BABY INTO IT. I HAVE NOT CHANGED MY TRANS OIL. I HAVE WATCHED MY TEMPS AND THEY HAVE NEVER GONE HIGHER THAN 175, USSUALY IN THE 165 TO 169 RANGE 99% OF THE TIME. I EXPECTED BETTER THAN THIS. ANY THOUGHTS?

[@kevbokubota4398]

I love your ram videos. I have a question about where and what filters I should get for my 2021 6.7. Should I get oem and if so is there a good place online to buy.

[@tintdr]

Geno,s garage for fuel filters and oil filter and air filter. I change my oil every 7k to 7500 miles. Because diesel engines are expensive and oil and a oil filter is cheap at Wal-Mart. I run Mopar oem filter from Wal-Mart and Rotella t6 5w40 all year round. Half the year in Florida and half the year up in the Catskill mountains n.y . If I can't find t6 I run the Cummins endorsement big blue extreme 5w40 and every 15k miles I do air filter and fuel filters. Very important to change the air filter on a turbo diesel.

[@joshpodolsky7740]

4low in these trucks is insanely low. With the 4.88's in our 5500s I think in 1st gear they'll idle at like 2mph. It feels like you would be able to pull a house down with the torque.

[@czwarlord9243]

Radiator being plugged doesn’t have anything to do with the trans temp. Transcooler sits in front of the radiator

[@TimGtmf]

I have 2020 ram 3500 HO aisin temps sometimes fluctuate between 168-210 in traffic without towing, I’ve noticed it happens when you have heavy traffic. Dealership said it’s normal operating temperature! My last truck never went above 170 on transmission but that was 4th gen HO

[@gb4807]

195-210 every day in vegas here

[@rideyz125]

Hey paul just picked up my 22 ram 3500 almost identical to yours I noticed it runs a bit warmer then I’ve ever seen my 19 Aisin truck get to just last week I got the trans to 189 and coolant to 219 pulling a steep grade with a lot of switch backs it was 103 degrees out didn’t hang out there for to long (pulling a 10k camper fully loaded). But my 22 seems to like empty at around 167 where my 19 wouldn’t break 164 no matter what empty.

[@joshpodolsky7740]

Those extra 3⁰ is nothing to worry about.

[@JosephRedmond]

My 2017 with Aisin ranges 165-195. I don’t think 185 is that high. The Ford we have the F350 and F450 regularly run 200-230 when towing. So I don’t think 200 for the ram is that high. Am I wrong?

[@newspaperlightbulb]

it depends on a lot of factors like driving conditions and ambient temperatures, as well as personal preference. 180-185 is a perfectly fine temp for the RFE to run at. I think even short periods around 200 you should be okay assuming it’s hot out. the hottest I’ve ever seen mine was just over 210 but that was because I was going up and down hills on a cattle ranch in eastern montana in low gear in 90 degree heat. if I regularly saw 200+ temps just casually driving around town I’d be worried.

[@mfboot.s1623]

Mine stays around 230-240 I haul across country and have a built trans

[@BackriverRebel]

I tow a 10k TT and never know how long I should idle with respect to oil, coolant and tranny temps. so I go with the manual that says 5 minutes.

[@edgardiaz5186]

Any idea why mine when it’s ideling tranny temps rises to 201? Then drive again drops to 168? The temps on this truck is always at 186

[@exogrid07]

thermal valve, or flow restriction

[@Firebird400]

Would you say the same for the 68rfe ? I had mine up to 212 on day towing the camper . You know the deal hot day, dirt road , big hill that went for a long ways and going slow . Fortunately there was the same downhill on the other side and got the temperature under control.

[@jlbush8249]

You were fine.

[@kache8778]

I have 2021 dodge ram 3500 in this thing with 100,000 miles it overheats to 274°

[@glnset-apart]

What is the largest inside diameter that hate transmission line should be?

[@chrisvolsicka1405]

Hey Paul I drive a 5th gen every day. I've been climbing good size grades and my temp on my tranny only gets to 165. Steep climb my oil temp and coolant temp will get about 215 and on the downside I kind of let the exhaust brake do its thing and the 5th gen seems to dump the heat off of the oil and the coolant have you experienced that in your 21 or any of your 5th gen?

[@jlbush8249]

Same with my 2021. Seems fine to me.

[@chrisvolsicka1405]

Thanks for letting me know I get a little worried when it hits 210 on the temp

[@jlbush8249]

@@chrisvolsicka1405 If it’s still in high gear, mine pulls like an animal and rarely wants to leave high gear, drop it down a gear and see if it cools it any. I’m sure the truck in monitoring the temps and would let us know if it’s a problem.

[@czwarlord9243]

On the freeway yes. Tow high altitude At 10pm high in 110 ambient temps it won’t be. I promise that

[@glenparks5175]

If they quit putting those damn shudders up front of the engine,then all these temps will go down, my ram 1500, I've seen the damn coolant reading 224 climbing a steep grade this summer ,so I'm going to remove half the shudders

[@MrErichonda30]

Think I've seen 171 at most on my aisin.

[@bobbyberrier8175]

186 trans temp is alot? My challenger rt 2022 sits at 195

[@vinceschannel8927]

My 5th Gen ram 1500 was at 180 tonight. Could there be a problem with that? Or is that normal?

[@Workingcockers]

Any follow up on you transmission temps going into the 180s? Mine Aisin has been steady at 165-167 and this week it’s been fluctuating between 165 and 190. I have no idea why.

[@vinceschannel8927]

@@Workingcockers no idea. I drove it hard one time and I checked it was at 200 something. Got me worried but she’s still shifting normally

[@carson3356]

I got mine 238 degrees before the clutches blew up

[@gerrylarson3675]

Thats Vantage. 10mi pull out of Columbia river

[@Dude-mz8su]

Every 10F above 180F cuts the fluid life in half. 220f is 2k miles at most.

[@joshpodolsky7740]

I think a synthetic atf can handle higher temps. 180⁰f is the rule of thumb for conventional atfs

[@RickyCrowSA]

Depends on the fluid -- the latest Ford 10 speed transmissions run 208-220F, towing or empty...

[@alfonsobernabe4291]

My built Allison runs at 200-210 on a regular hot day hauling 15000

[@zGhillie]

Do you delete your bypass or use another stock one? On my 16 it would run 200 empty till I got a delete for the bypass then it ran at 140. My 22 runs 160-180 empty and 180-190 towing since new.

[@justanotheraviator2357]

I have a 4runner, but my trans temp on my school bus runs 199/205 it runs a 2018 Ford 6.8V10 Propane and the 6 speed loaded or empty

[@dbarton8651]

Metaline falls area?

[@eugenep9022]

What if I have an Aisin transmission? Same temp levels?

[@alanb.4660]

Aisin should run 165-170. I have 38,000 towing miles with a heavy 5th wheel all over the country including up I70 in the summer. Never an issue with the Aisin because the torque convert stays locked at normal highway speeds...say above 20-30 MPH.

[@stoicsteel]

ATF degrades fast once it gets over 200 F

[@jonathonsmith7694]

must be a old man, LV does not

[@betterthanideserve76]

Negative, LV can go to 240 all day.

[@tintdr]

You did not mention EGT,s

[@FosterStrongman]

When we getting the duramax content Paul?

[@DaltonP2156]

Manual says 175 is optimal temp

[@coquitlamtowingportcoquitl2405]

Holy f 5 mins watching still nothing about what’s the highest temp 😂😂.

[@coquitlamtowingportcoquitl2405]

Get to the point of your title in first minute

[@Workingcockers]

My temps on my Aisin have been steady at 165-169. This week my temps have been fluctuating between 165 and 190. I think something might be wrong with my transmission. Why the wide fluctuations? Any ideas? My truck is deleted but I have only run it in stock tuning.

[@TimGtmf]

I have 2020 ram 3500 HO aisin temps sometimes fluctuate between 168-210 in traffic without towing

[@doneB830]

I have a thing in Australia to start taking care if you go more than 50 deg C or 122 F above ambient temp as a guide.