just an FYI:
for the guys that want to run a heavier oil in their tranny, there is a big misconception on oil viscositys out there.
First of all, motor oil and gear oil weights are measured on different scales. With that said, a 75-90 gear oil is actually about the same in viscosity as a 10w-40 motor oil. So a 20w-50 is thicker than the 75-90 gear oil, and a strait weight 50 motor oil is thicker yet.
If you are looking for a good heavy oil to quiet down the tranny consider a strait 60 weight motor oil.
Amsoil just introduced MCS 60 for exactly that purpose, ask your Amsoil dealer about it. And no, I'm not a dealer, just did some reasearch on it.
keep on ridin..