Harley M8 - Step by Step Change Transmission Fluid

[@DKCustomProducts]

I have almost 10 thousand miles with the HD Heavy Gear Oil in the trans. It is definitely good stuff...almost as good as redline. But I will be putting in redline next go around. To me the redline shockproof seems a bit smoother. However, if Redline were not available I would be perfectly happy running the HD Heavy Synthetic Gear Oil in the trans...well, except for the price. 😬

[@Whiskeybende]

Wonder who makes it.

[@tax905972]

Big chips sucks. with syn3, never see that crap with syn3. change the ring it's cheap.

[@schachat01]

I switched to the HD Synthetic 80W-140 on my 2008 FLSTC Primary and I have found that the OEM Compensator and clutch runs far better than when I used the SE Syn3 20W-50 oil. Bike has done about 68,000 kms and I have maintained the bike myself pretty much from day 1.

[@DKCustomProducts]

Good info to know. Thank you. I know they say it is for the primary also...I may give that a go next change.

[@talkingrock7011]

Kevin I change all 3 holes every 5000 miles and I always use Amsoil synthetic primary oil ,& engine & transmission and have been happy with it , ride safe sir !

[@DKCustomProducts]

Thank you, you too! A lot of folks do what you are, and have very good experiences themselves. Thanks for sharing! 👍

[@Whiskeybende]

Just received my BelRay 10w-50 synthetic oil in today for the next oil change. Was running Ams for for years. Just put in Redline 20w-50 and there might be a slight reduction in the rocker clatter but not much. Nature of the beast. Ams, Redline, BelRay, Maxima, Mobil 1 are all good oils with great reputations.

[@DKCustomProducts]

Yep, as long as it is lubricating your internals it really doesn't matter. Thank you for commenting! MB

[@BackRoadKing]

I tried the HD gear oil around 10K on my 15 King, but found absolutely no difference. So switched back to Amsoil again all 3 holes. Willing to try Redline if you go running back. Have a great trip, DK Rocks!!!

[@DKCustomProducts]

Thanks for sharing, will do a follow up after a few thousand miles to see if I can tell any difference. As of right now, with about 500 miles, I am not really noticing any difference.

[@easyglider1307]

I used the HD heavy gear oil at the 5000 mile service. Meh it was OK. I switched to the Redline Tranny Fluid with shockproof and a big difference. Much easier finding neutral and the shifts are buttery smooth.

[@DKCustomProducts]

Thanks for your input. I still only have about 500 miles with the new gear oil in there. So far I have not noticed any difference. We'll see over the next few weeks and a few thousand miles what it feels like to me.

[@jimbo4260]

Redline shockproof is thick as heck right,?

[@easyglider1307]

@@jimbo4260 That stuff looks like thick Pepto Bismol. I have since switched to Amsoil tranny oil. That stuff makes the shifting smooth as butter, I also use the Amsoil primary oil. Can find neutral really easy and the primary is quiet.

[@michaelrocole7174]

Like always good detailed video. I change all three fluids with every oil change. Pennies on the dollar or O-rings are cheap change them. Thread tape can migrate. I see no reason to use it. I run Amzoil all three holes. Many great products out there. Good video.

[@DKCustomProducts]

Thank you for the input...and you're right, there is no need for tape or paste, just a habit. Glad you liked the video, thanks for the comment.

[@ericroadking7564]

I have bee running the Amsoil Sever Gear oil 75 / 140 in my new M8 has reduced the clunk quite a bit can't even hear the 1st to second gear shift!!

[@DKCustomProducts]

Nice!

[@Greenjeans2020]

I'm a firm believer in "gear" lube for the transmission. Synthetic or conventional, as long as it's gear lube.I have used Red Line in the past. What's nice about Red Line is if you have a leak, you can tell if it's from the transmission. With that said, I have been using Amsoil Severe Gear 75W140 since new on my 2020 Tri Glide. Shifting is very smooth and I suspect the Harley version will be just as good.

[@DKCustomProducts]

Glad you found an oil that works well for you and your transmission. Thank you for commenting! MB

[@Whiskeybende]

I was using Ams severe gear also and a builder turned me onto BelRay 85w-140 and I noticed the difference he was talking about. The good and the bad thing is there are so many choices to choose from and a lot of them are great choices! Redline, Ams, BelRay, Mobil 1 are all top notch manufacturers with outstanding products. And I couldn't agree more with you on gear lube for gears.

[@darrenlingerfelt5879]

Dang!! 😮 I change all 3 holes every 2,000 miles on my 2014 TriGlide.

[@DKCustomProducts]

Wow, that's a lot. Not going to hurt anything. But, I have a question, what kind of temps are you riding in? Another question, about how many times per year do you change all 3 holes?

[@tcatnat70]

Redline and Spectro are my preferred brands for the tranny. I have Lucas in there now and just bought another bottle of Redline to change it out. It shifts fine with the Lucas but man it got a lot more clunk in it when changing gears. Redline and Spectro are the best at quieting it down.

[@josephzieroff2631]

This is all i have used in my transmission from the first oil change. I also use it in the primary. Two things i noticed, cooler primary and the clutch does not need to be adjusted as much. I do quite a bit of slow speed practicing and have checked the adjustment many times. I have not been able to detect any change in the clutch adjustment. If there is any it is very small. I'm not sure of any temp change in the transmission.

[@DKCustomProducts]

Thanks for sharing.

[@rickcollins4086]

I use this product and I'm very satisfied with it I bought a new Road Glide Special when I go for my Thousand Mile service I will have them put this in the very good product

[@DKCustomProducts]

I am liking it as well! Thanks for commenting! 👍

[@garyr193]

What are your thoughts after using Heavy Synthetic Gear Oil. Thanks gary

[@DKCustomProducts]

I have almost 10 thousand miles with the HD Heavy Gear Oil in the trans. It is definitely good stuff...almost as good as redline. But I will be putting in redline next go around. To me the redline shockproof seems a bit smoother. However, if Redline were not available I would be perfectly happy running the HD Heavy Synthetic Gear Oil in the trans...well, except for the price. 😬

[@rykerolaoghaire8781]

Thank you for the info! 😎

[@DKCustomProducts]

Good you hear you liked it!

[@TheYulick]

Hi Kevin, how are you! I have to change the oil on my Milwaukee Road Glide M8, but here in Brazil, we can't find Formula+ to buy and unfortunately each workshop suggests a type of product. But how will I do the change at home, which oil could I use?? 75w90 gl-4, 80w140, 90 gl-4...??? help me please. Thank you very much! 🤜🏻🤛🏻

[@DKCustomProducts]

Depends on the year and model bike, also on your lowest ambient temps. You ask about formula+, so maybe your question is about the primary. If it is the primary, or the primary/trans combo on a Sportster, then a good motorcycle rated 20w 50 will work fine.

[@paintballjunkie65]

I know it has only been 6 weeks, but have you noticed any difference yet? And are you thinking about switching back to redline?

[@DKCustomProducts]

It has been long enough. It is not quite as smooth shifting as with the Redline Shockproof, but definitely better than what HD used to recommend for the transmission. If I could not get redline shockproof, this is the trans gear oil I would run.

[@toddgittins5692]

Non-hardening pipe dope. Is how you seal those plugs, as told to me by a friend, who is a 30+ year dealership mechanic. Great video!!

[@DKCustomProducts]

That will work too...I prefer the teflon tape over the paste, easier for me to work with. Reality is that a good o-ring is what seals it, the tape on my part is more just an old habit. Glad you liked the video, and thank you for the additional info!

[@toddgittins5692]

@@DKCustomProducts you're right, O-ring and done. For some us that are borderline OCD, we want that case dry and just a little of the dope will seal the threads. When you're working in a well stocked shop, it's beyond easy to do. For Joe 6-pack, inspect/change O-ring, would be fine. Keep up the good work, really enjoy/learn from your videos!!

[@DKCustomProducts]

@@toddgittins5692 I hear ya on the borderline. lol Glad you're digging the videos, and thank you for your comments!

[@bajarvcouple]

Understandable step by step

[@DKCustomProducts]

Thank you. Hope you both are doing well! 👍

[@billmcdowell9739]

Kevin, I have run Redline for the last 20 years, were you happy with the harley oil or stick to Redline?

[@DKCustomProducts]

In the Trans, it is right up there with Redline shockproof...in my experience. In the primary, it may be the best things I have run in it. Here is a video that you may find interesting- kzbin.info/www/bejne/mH-rmIGKndekh9E Thanks for commenting! 👍

[@travismiles8635]

Do I need the bike warm or standing straight up to check the trans fluid. I put the 28oz in and it's barely at the bottom of the dipstick

[@DKCustomProducts]

For checking the transmission fluid, you will want the bike standing straight up on a jiffy stand or something to that nature, and you will want to check the transmission fluid at room temperature not warm or hot. There should be an "A" and an "F" you will want the transmission fluid in-between those two letter marks. Thanks for watching!

[@travismiles8635]

Thanks brothers. You guys rock. Going to be ordering my intake and catch can anyday now

[@DKCustomProducts]

@@travismiles8635 Good deal, man! We appreciate your business! Thank you for watching our videos, ride safe!

[@stevekampney6440]

Where did you get your engine oil dipstick temperature guage?

[@DKCustomProducts]

We get our Oil Temp Gauge dips sticks from JES Customs. Kevin has used it for years. www.jescustomaccents.com/ Thank you for commenting! 😎 MB

[@shrakkem]

curious question your oil dipstick gauge where did you get it?

[@DKCustomProducts]

We have been running JesCustoms analog dipsticks for a few years. Very pleased with them. 👍

[@richardrussell500]

Great video... Thanks :-)

[@DKCustomProducts]

Glad you liked it! Thanks for letting us know.

[@cjangula77]

@DKCustomProducts what engine oil temperature gauge is that?

[@DKCustomProducts]

It is from JES Customs. Kevin has used it for years. www.jescustomaccents.com/ Thank you for commenting! MB

[@rfuller5657]

Kevin, what is the brand of the temp oil dip stick? And, I change all 3 holes at 5,000 miles. Over the years, it seems Harley has lengthened the oil change intervals, but not the component materials the oil protects. EPA thing?

[@DKCustomProducts]

The temp dipstick is a JESCustoms. I've been happy with it. That is a good question about intervals. Not sure if it is an EPA thing, or just the oil has gotten better. Here's another video on oil we did that you may find interesting/useful. kzbin.info/www/bejne/mH-rmIGKndekh9E

[@rfuller5657]

@@DKCustomProducts Thank you Kevin, not cheap dipstick, but looks like quality! I follow Kevin Baxter/ Pro Twin Performance and I'd be surprised if you haven't heard of him. He makes sense, just like DK Customs. I think you guys do very good research and testing work of products and really like theory and products backed by facts. Example? All of your cooling products are tested and charted. Go to 29:30 of his video where he talks of no component change, yet extended change interval on primary and transmission oils for what he believes is "carbon points". This is where it made sense to me to just do a 3 hole change every 5K. Thanks for your products, and for the videos. kzbin.info/www/bejne/nJzOamOap9R0mLM

[@DKCustomProducts]

@@rfuller5657 Thanks man. On a road trip right now, but when stationary in a few days, I'm going to watch the video. Thanks for the kind words.

[@DKCustomProducts]

Just watched that section of the video. Yeah, I knew that, and then forgot it. Thank you for the reminder!!!

[@rfuller5657]

@@DKCustomProducts From what I've heard, he's a heck of an engine builder. If your road trip comes through central Arizona, give me a holler...

[@jackklarich7045]

I use Permatex brush on Teflon, IMO it is more user friendly

[@DKCustomProducts]

Hey Jack, thanks for the additional info!

[@CAngel-gq8cm]

I always used the Teflon in a tube or tape on my 97 evo the last 25 plus years at every fluid change. I just did my first 3 hole fluid change myself in my new 2023 Street Glide and I see so many folks suggesting teflon is no longer required I decided NO MORE TEFLON! If I ever see a drip of fluid i'll go back to my trusty Teflon as I'll admit, a Teflon habit is hard for me to break! But boy it will be nice not having to clean and remove old Teflon from the threads next fluid change! I think I will however, always use new O-rings but I hope my days of needing Teflon are over! I got about 200 miles on my Teflon free fluid change with no drips so far but time will tell! I did however notice my Harley dealer DID USE Teflon on my bike at its first 1K as I had to clean the white teflon off the threads! Things that make you go Hmmmm?

[@bigdaddy5948]

I wonder if Valvoline V twin 20 w 50 is ok. Full synthetic

[@michaelsnyder1162]

My cuzn uses that on his’14 heritage & has no issues At All

[@DKCustomProducts]

I am sure there is no issue in the trans, but my thoughts are, why use motor oil in a gearbox? Why not use gear oil in a gear box? We talk more about oil in this video- kzbin.info/www/bejne/mH-rmIGKndekh9E

[@bigdaddy5948]

@@DKCustomProducts been using synthetic 3 Harley fluid in all three holes for over 80 thousand. No issues

[@roncoburn7771]

I stay with redline in trans in primary and driven in my 128 motor no harley stuff in my bike

[@DKCustomProducts]

Understandable.

[@1963KILO]

Stupid question: in the diagram of the 3 plugs......what is Plug #3? What happens if it is removed then reinstalled?

[@DKCustomProducts]

That is the SUMP plug! 2019 and earlier M8's had a problem with sumping and one of the big issues was that the sump plug was too long not allowing adequate scavenging of the oil. Although the diagram says do not remove we sell a shorter sump plug to replace the OEM sump plug on 2019 and earlier M8's. Here is a video on the subject if you would like to know more-kzbin.info/www/bejne/lWXaqXmgpt6Hd7c Thank you for commenting! 👍 MB

[@louiedee279]

My plug is on the left side , I have a 2017 harley touring limited.

[@DKCustomProducts]

Yes, as mentioned (and shown) in the video, the transmission drain plug on an M8 is on the left side of the bike. Thank you for commenting! 😎 MB

[@fighttechnician8676]

My 2017 street glide transmission takes 1 quart

[@DKCustomProducts]

Capacity varies over the years and models.

[@darrenlingerfelt5879]

😎👍

[@DKCustomProducts]

Thank you!

[@Whiskeybende]

So Harley used to claim their 20w-50 motor oil was good for the transmission and now they say 80w-140 is the way to go? The other oil manufacturers and motorheads already knew this.

[@DKCustomProducts]

Yep...the 20w-50 motor oil worked, but not nearly as well as actual gear oil. 😂 KP

[@Whiskeybende]

@@DKCustomProducts I think anything will work if it's fairly short term use. The fact is gear oil is just that. Oil made to withstand the pressures put on gears and other lubrication. I used Syn3 in all 3 boxes at one point too because HD recommended it but it's not magical oil. It's 50 weight motor oil but since HD recommended it I used it. I have come to find out that manufacturer recommendations are not always the best recommendations. Especially when they say 50 weight motor oil is fine for your transmission and now they are saying 140 weight gear oil is the thing to use. That's a significant difference in oil weight and that's also when I start to see through the hype.

[@DKCustomProducts]

50 weight motor oil is equivalent to a 90 weight gear oil in terms of viscosity. Motor oil and gear oil have different standards and specs. But the differences (beside viscosity) are substantial. Best to use gear oil for the trans. What really surprised me is that HD is now recommending their 80w-140 gear oil in the primary! KP

[@Whiskeybende]

@@DKCustomProducts when I used to hang out at the my local Harley shop an employee bought a Screamin Eagle bike. (I can't remember what model for the life of me) and they're supposed to come with fluids from the factory. Well the dealership never checked to see if it had any fluids and he rode the bike 100 miles home (yes he actually lived 100 mi away from work. Retirement.) Anyway he noticed it getting hot on the way home so he checked everything out. Turns out the bike had no oil in the primary. He got an entirely new primary from HD. Point is it's impressive with how far they can go with basically nothing. I wouldn't recommend it but it's a pretty neat story.

[@Whiskeybende]

@@DKCustomProducts I think putting gear oil in the primary is a waste but at $20/qt I'm sure they'll recommend it for anything. Been running ATF for years now recommended by Barnett Clutches.

[@Greenjeans2020]

While not a fan of synthetic for the engine, I do like it for the transmission. Gear oil is completely different than engine oil. I have been running Amsoil 75W140 severe gear in the transmission. Shifts great even in cold weather and a recent trip in Arizona in 95 degree heat. I think folks are foolish to run engine oil, synthetic or not, in the transmission. Run gear oil, synthetic or not, as long as it's gear oil!

[@DKCustomProducts]

Thank you for the additional info. Here's a video on oil that we did that you may like- kzbin.info/www/bejne/mH-rmIGKndekh9E

[@tax905972]

where trans takes the entire bottle!!! You should flush that redline mess out before you use the syn3.

[@DKCustomProducts]

Thank you for your input and for commenting! 👍 MB

[@thevoyer2002]

How come no one knows how to put teflon tape on correctly?

[@DKCustomProducts]

That is a query that I ask myself everyday!!! 😂 MB