Primary lube
Cruiser
Joined: Aug 2008
Posts: 190
Likes: 25
From: Rotterdam, Netherlands
Absolutely agree on the ATF. I'm sure your stator will love you for the extra cooling it gets from it
Cruiser
Joined: Jul 2015
Posts: 166
Likes: 13
From: Beaufort, NC
Gear oil has a different viscosity scale than motor oil... 75w90 is actually pretty damn close to 20w50 motor oil, and the 50 weight engine oil. So long as you don't have something with some slick **** in it meant to be energy conserving, no problem. Particularly with the stock clutch.
https://www.bobistheoilguy.com/wp-co...1/ISOchart.png Click that and poke around... Stuff isn't what it seems event though the W in the middle makes it feel like it ought to be. Then again, you don't ever squirt motor oil out of the little nipple on a gear oil bottle to see how they compare either.
https://www.bobistheoilguy.com/wp-co...1/ISOchart.png Click that and poke around... Stuff isn't what it seems event though the W in the middle makes it feel like it ought to be. Then again, you don't ever squirt motor oil out of the little nipple on a gear oil bottle to see how they compare either.
Road Warrior
Joined: Apr 2007
Posts: 1,952
Likes: 15
From: Senoia, Ga., by way of Miami, Fl..
I started using the 75w140 as a Ford tech, it was easily available.. the coments on GL5 and it makes good sense... I can say, I've never experienced trans has never shifted better or quiter.. I'll probably reconsider that..
As for the ATF, I started with it because the HD clutch is so similar to an auto trans multi disc pack. Again, I think it helped the shifting and it's cheaper than primary fluid..
As for the ATF, I started with it because the HD clutch is so similar to an auto trans multi disc pack. Again, I think it helped the shifting and it's cheaper than primary fluid..
Advanced
Joined: Oct 2014
Posts: 99
Likes: 5
From: Fort Worth TX
My energy one clutch plates specify type f trans fluid. I believe other manufacturers do as well. ATF has been used for years in some automotive manual transmissions. If anyone is interested-I have other things to worry about- 20w 50 Castrol GTX in motor, type f in the primary, Lucas synthetic gear oil in the trans. The sporty gets the same with the obvious deletion of the type f. Lucas synthetic in trans. Im still waiting for the stator to die or brass to melt as I was warned 10 years ago from using gear oil but I dont see it happening after all this time.
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Cruiser
Joined: Nov 2017
Posts: 246
Likes: 20
From: Front Royal, VA
I too am interested in the ATF fluid instead of primary oil. I just replaced my clutch (BDL), Spring plated and chain tensioner. A recommendation on what ATF to use? BDL say's not to use synthetic lubricants on their clutches.
Road Warrior
Joined: Apr 2007
Posts: 1,952
Likes: 15
From: Senoia, Ga., by way of Miami, Fl..
The clutch material and characteristics are what dictates the blend. Personally, I've always looked at Harley as a very primitively engineered machine, so I never gave it much thought... with that said, I use merc III, because that's what I had. Since the clutches have already been saturated with that blend and additive package, that's what I stick with.. the better suggestion would be to ask the clutch manufacturer what they recomend.