This probably has been discussed but my search didn't bring much up. Long story short I dropped my bike off at the dealer for the 1k service this morning with customer supplies fluids and the service advisor asked why I had some syn3 and some fluid that is specifically made for primary and trans (all bought from the parts guy at harley). I told him that's what the parts guy said I needed. Then he said to me "that's because he is an idiot"...

Basically the parts guy told me that the primary and tranny fluid has additives made especially for them that the syn3 oil doesn't have.

I just wanted to see what you guys here thought.

Thanks.

 

This is one of those things that can be debated forever, and both sides have good arguments.

The one camp says that the lubrication needs of an engine, a primary drive, and a transmission are all different in some ways, despite having some commonality too. So, they argue, if you want the "best" protection and performance, you should run a specialist lubricant in each, since no one lubricant can be optimal for all 3 uses.

Some very experienced engine and race bike builders, including Mike Lozano of Lozano brothers fame, insist that both the quietness and performance of primary drives and trasnmissions are enhanced by using specialized lubricants.

The other camp says that although either (a) the above is true, or (b) it USED to be true, nevertheless, modern lubricants are so good, and modern materials and parts tolerances in engines/tranmissions/primary drives are so good, that one lubricant CAN in fact serve "more than well enough" in all 3 usages, with the life of those assemblies not being adversely affected.

This camp further argues that by using just one lubricant:

1. Maintenance costs are lower for the owner, since you don't open up 3 separate lubricant containers, and use less than 100% of each

2. The chances of a mechanic or owner making an error and pouring the wrong lubricant into any of the 3 reservoirs is eliminated

3. On many modern Harleys, there does NOT appear to be any regular lubricant loss or consumption, but If there is any lubricant usage at all, the owner needs to carry only ONE container of lubricant, versus 3, to cover all potential needs.

I could personally go either way on this . . .

And, I wouldn't call anyone who takes EITHER view an "idiot".

Jim G

 

SNY3 or F+ makes little to no difference except cost. There is not down side to running quality sny in primary other than cost. Seems to be nothing gained by it either.
Go by what you see in front of you:
I know a lot of riders that logged a lot of miles I am one of them. It has made No difference what any of us have run as far as primary lube, Transmission lube or engine oil.

 

Thanks for the info guys.