Put some dye in the transmission fluid and put some miles on it. When it gets low check your primary and motor oil for dye.

 

FWIW.......

There is a thread on another HD site I read regularly. The title is, "M8 trans fluid leaking in primary."

There are a few people finding, at service intervals, that their trans is a few ounces low, and the primary is a few ounces high.... They are debating how it could be possible, and most think it has to do with the design of clutch pushrod.

One person claims their dealer caught it at a service and a MoCo rep is going to inspect the problem....

If you google the thread name, it should take you to the forum link, interesting read...


I just noticed there is a thread on this forum about the same issue, "Gear oil Level"

 

I use gear oil in the tranny and Rotella in the primary.. I could smell the gear lube in the primary the last time I checked it.

 

That sucks. I used amsoil 20/50 in the engine and trans and formula+ in the primary in previous bikes because the amsoil didn't feel great in the clutch. Guess I'll have to see how it feels in the new ride so I'm not mixing fluids....

 

If you want to make your 2017 M8 transfer fluid, its easy to do it. Check and set levels before the test so you know where your at. Run engine in the 4000 - 5500 RPM range while riding for 5 minutes of operation. You can do this in any gear you like but 2nd is just fine and your not pushing way to much vehicle speed in 2nd. You can do it on the dyno too if you have one, just place a small load on the bike < 5% is fine. Recheck fluid after testing and the transmission will be low. If left to itself and you operate at these RPM levels for longer periods of time it will transfer all but about 4 oz out of the transmission. I have done it in 2 - 4th gears and it makes no difference. It is completely RPM driven.

 

So is the fluid moving around the clutch pushrod?
If not, where?

 

Please Steve some questions: Is this a new issue or did earlier TC's have the same problem? Have you investigated and noted a reason and maybe a fix?

Gary in Alaska

 

I'm just glad it doesn't flow from the primary to the transmission, as the service manual states that mixing synthetic and mineral-based fluids in the transmission will cause transmission damage...

 

Friction modifiers commonly found in transmission fluid will cause a wet clutch to slip. That's why trans fluid smells.

 

I recommend you use the same fluid in both sides for the time being. The manual recommends Formula plus in both and I believe that is how they come from the factory. The simple fix is do not run the engine above 3500 for extended periods of time and if you do, you just need to keep an eye on the transmission fluid level.

This is new to the M8 application as I own a TC with the A&S setup and have never had the issue. I am not going to say it cannot happen on the TC but I have just never seen it. The M8 on the other hand we found it very early on in our testing. Thought it was not right so did similar testing on another M8 bike and it did the exact same thing. So far we have kept track of it on several more M8 bikes and they all do it. We found what causes it and know what we have to do to avoid it, and what to do when testing requires us to run in those areas.

We have tried just about every fluid people say they use and it doesn't matter what you put in the transmission as it is going to transfer to the primary, been there done that! So for us it back to Formula plus in both and just keep an eye on it.

We believe we know why and what it will take to fix it but until we prove it out, it's just more theory and to tell you the truth I just did not want to be the one who brought it up. When mjwebb had issues, I explained the issue to him and what he needed to do to avoid it. He took my advise, did his own testing and on his bike came to the same conclusion as I did.