Forgive me if this is a stupid question but just did my 1,000 mile service this week end and switched to Mobil 1 V-twin 20w50 for engine and primary and Mobil 1 75w90 gear lubefor the tranny. The gear lube seemed very thin compared to the 20w50, I thought it would be thicker. Am I missing something?

 

Synthetic oil seems thinner than dino oil.
I use MCV 20-50 amsoil in my motor and primary and went with the SVO 75-140 in the transmission.

 

Gear lube viscosity numbers don't equal motor oil viscosity numbers. Just from eyeballing it, 70W90 gear oil is probably closer to 30 or 40 weight motor oil.

 

The 75/140 Mobile 1 worked better in mine. It just feels smoother. I'm running 75/90 now, but I will be changing back.

 

Why did you feel you had to go 75-140 over 75-90 in your trans? I use 75-90 amsoil in my 08 sg and it seams plenty thick.


Ride On!!!

 

I used 75-90 in my dyna........ not enough miles to change yet on the SG

 

After lots of research, I plan to run:
Engine - Mobil1 20w50 vtwin (if can find vtwin)
Tranny - Mobil1 75/90
Primary - HD Formula+

 

I'm running the Redline Heavy Shockproof gear oil in my trans and it is by far the best of all the syns I have tried, including the Mobil 1.

 

90W-140 is used in 80,000 GVW 18 wheel trucks....what kind of load are you hauling to need that kind of gear lube?

Seems a little extreme for a 1000 pound motorcycle, don't remember seeing that in my HD manual.

Why don't you guys that feel you need to use this high viscosity lube just pack the tranny with grease like boat wheel bearings?

What the heck does HD know, they just build the bikes!

 

Does synthetic in the tranny make the ride feel smoother than dino?