[QUOTE=V2Evo96;5006723...I don't think you need Syn in there, but whatever you prefer is fine with me.[/QUOTE]

Got this from another forum...
"Although the primary doesn't generate much heat in and of itself that's not the only concern when choosing a fluid.
The primary on your motorcycle is not a seperate entity. It is attached to the engine and it acts as a giant heatsink for that engine.

The temps seen on a long hard run are probably within 20-40 degress of the engine oil temp. Mineral based ATF starts to break down at around 220 degrees and is almost useless as a lubricant at 250 degrees.

On most Harley's the rear exhaust is in close proximity to the primary case and that adds heat too."

The use of a synthetic ATF might be helpful for those that see high engine temps and consequently high primary temps too.

 

This is why I'm asking the question dude. I want to hear what people who have experienced with ATF have to say. Btw, we all know Harley-Davidson has everybodys best interest in mind right...

 

All the mechanics at my dealer use ATF. They asked me if I wanted ATF at my 1000 mile service.

 

Been using the B&M Trick Shift in my 93 FXLR for a couple of years now for a couple of reasons.

(1) It is reccommended by Dean from Energy One for use with the clutches he builds that I use.

(2) I have had some expierience using the B&M Trick Shift fluid in an automatic equipped Hemi powered 1968 Dart SS/AH. The Hemi three speed automatic uses an 8" 5000 stall speed converter at some races. These converters produce extra heat and slippage during burnouts and those 1/4 mile runs. Never had a fluid related failure with either the race car or in my bike.

 

Dealers don't carry "Primary Fluid" anymore, though you can still get it at a decent aftermarket shop. Like Miacycles said, ATF is used in even extreme automotive transmission applications (even buses and trucks) so you can't go wrong with that. Also, being thinner it will disspate heat quicker.

If you want something a little heavier and "primary fluid" isn't readily avaliable, use hydraulic fluid. Yep, just like goes in a farm tractor or any equipment using hydraulics. The PTO clutch of a tractor is virtually the same as the HD. That's what the "primary fluid" actually is (was) that HD sold for many years. And if you're a stickler for the right stuff, use "type" R & O which is specifically designed for chain applications as well as fluid clutch use.

 

Thanks for all the responses guys. I'm going to give the B&M trick shift a try when I find some. I think hey have some at a car performance shop around here. Thanks again.

 

Hey Mike,

Been using Dexron II for 20,000+ miles without issues and the clutch hooks great. Word of advice, Trick shift will hook harder, so slipping the clutch for slow speed manuevers becomes more of an issue, same with Type F, although it doesnt hook as hard as the trick shift.

As far as the recommendation that HD has been doing this for 100+ years, their products are ok and provide decent service, but there is always something better out there. And for those that have dealers recommending the ATF, those guys are on to something !

 

I do have concerns about the noise. I took the primary cover off and the only thing i could find that would make noise was the auto chain adjuster.

 

Dextron II it is then. I've always value your opinion for gold. Thanks Dalton.

 

I buy mine locally at Autozone or Advance Auto for about $5.00 per quart. There are better deals online, but after the Hazmat and shipping charges it's cheaper to buy locally. I also get my Mobil 1 75/140 (they also carry 75/80), transmission gear oil there tool. The fluids in my bike are changed often for piece of mind.