



Those using an 80W or 75W-90 in their transmissions are actually using a much thinner oil.

So those opting for a gear lube thinking that they are using thicker oil, really are not. It is approved for use on the 2019 FXBB 114 applications. Hello Splat, This Formula+ Transmission and Primary Chaincase Lubricant is approved for use both the Transmission and/or the Primary Chaincase applications. What is transmission and primary chaincase lubricant approved for? IMO you don’t need a gear lube in the HD tranny. What kind of spectro oil does a Harley Davidson use?ĭown there – the heavier grade GO (75W/140) would be best…order your Spectro Oil online…that’s what I did. Answer: For any Harley Twin-Cam engine, we highly recommend using AMSOIL Synthetic 20W-50 in “all three holes” (as they put it) for two essential reasons. Some even use ATF in chaincase and claim they have great results. Some use gear lube in the transmission and chaincase. What kind of lube do you use on a Harley?
