I use the Amsoil filter with 20w50 in engine & primary & 75w140 for the transmission. Smooth as silk.

 

agree with amsoil 75/90 in the tranny much smoother shifting over syn 3 but in the pimary? i use 20/50 same as in the engine. oops sorry just read your follow up

 

I switched to Amsoil at the 1000 mile mark on my 07 Ultra. 20w/50 in the motor and primary and 75w/140 in the tranny. Trany is much smoother and much quieter. I liked it so much I became a Amsoil dealer and so far have 50% of the guys using it in their trucks. They like the 25000 mile change intervials. IMHO it is the best oil on the market.

 

why does amsoil recommend 20/50 in all 3 holes?

whats difference between gear oil 75/90, /110 and /140...higher # thicker?...i always forget

and before you wiseguys say it, yeah yeah 20 and 50..lol

 

the higher the number the thicker the oil is

 

Good stuff. been running Ams-oil Sever Gear75/90 in tranny from day 1 last 3 Harleys.

Primary running HD plus.

 

I didn't care for 20/50 inthe tranny, liked the 75/90 then stepped over to Redline shockproof. Tranny has never given me problems but it is smooth as butter during the Texas heat.

 

The Amsoil sight has a good, better, best scale onit. They recomend 20-50w in all three holes as good and then you can upgrade.
I use 20-50w in the engine and primary and 75-110 in the transmission.
Works great!!!!!

 

Same effect, different synthetic oil. Any high-quality synthetic gear oil should provide smoother tranny operation. And, yes, an expensive oil in the primary is overkill.