Have a 17 RK Special M8. I just put RedLine (red creamy stuff) tranny fluid in replacing the Formula+ crap, much, much smoother tranny action.

Question is, if my Redline fluid migrates into the primary as I been reading with some that have that issue, I don't know how the clutch would react with the Redline tranny fluid.

Should I revert back to an multi-purpose fluid like Formula+ in case? I am not a fan of using a multi-purpose oil in my tranny.

 

"replacing the Formula+ crap"

"Should I revert back to an multi-purpose fluid like Formula+"

if you think it's crap then I don't recommend you use it...just stick to the twice as expensive stuff you're using as long as it's compatible

I prefer the 'crap'..compatible, works great and isn't way overpriced

 

tried several tranny fluids over the years on numerous bike - Formula+, Amsoil tranny and Redline - the Redline has given me the smoothest shifting action.

I don't see how an multi-purposed fluid works best in engine, primary and tranny. There will be compromises using one oil in all three. Reading the white papers on the oils by Amsoil, the HD oils do not do well. Some of it could be marketing, but Amsoil in the engine and primary seems to be smoother and cooler running than the HD fluids.

 

I get your concern. I'm an amsoil fan and have run the 20/50 in engine and trans in many bikes but don't like the clutch feel with it in the primary. Now I'm running amsoil 20/50 engine and trans and formula + in primary. 2800 miles in and no sign of migration yet but if that becomes an issue I'll go formula + in trans as well. Not a big concern as all oils must mix together but I just haven't had great experience with syn in the primary.

 

For those that run the same fluid in all 3 holes, what is your reasoning? I've never understood the concept of not using a fluid that is more setup to be used in a specific location. As for the multi-purpose fluids, kinda makes you wonder if HD knew of or expected this migration deal to be a problem.

 

Not sure but. Hard to prove my tranny started leaking switch over to Spectro Heavy duty platinum at the time I paid 23.99 its now 26.99 what the heck i was thinking???. It did work better the tranny was a lot easier to shift and get into neural seemed smoother. Had 4000 miles on the Bike that's when the leaking started, had to add more oil about every 1000 miles can't blame it on the Oils i was running the RGU pretty hard RPM over 3500. Started reading on problems others were having.
On the 3rd time the tranny got low i brought to the dealer listened to there crap but they were going to get more info on a dye test. I just did a trade back couldn't get use to the Road Glide had 6000 miles on it. I found out i have some perception eyesight problems . Turns out I shouldn't of been on the Road Glide with these problems. Perception And the shark nose don't mix Hopped on Electra glide ultra classic this is the motorcycle for me love it.

 

any oil experts out there? if a gear oil mixes with the primary oil - any potential clutch issues?

 

Not if you use the same oil in both.

 

I use the syn3... Because it's easier to buy one, use one, and I've never had any issues using only one. That's my only logic... Could another type work slightly better... I'm sure it's very possible, but for me.. if it ain't broke... don't fix it...

 

Every modern manual transmission that I am aware of runs either ATF or some weight of motor oil. It seems only Harley folks get worked up over running gear oil in the transmission. And gear oil was actually designed for differentials. I only point this out as I have run just about every thing in my Harley transmissions over many years. And I cannot tell a bit of difference in any of them. I have zero hesitations about running 20W50 in the transmission. Hell, it is what Amsoil and Mobil 1 recommended for years. And might still for all I know. I had a Mobil 1 engineer tell me its what he runs in his HD Trans.