Hi, i bought this fluid a while ago and now that I have my FD, would this be safe to use for trans and diff? The reason why im really asking is because this is Gl-4, and i searched for Gl-4 nothing came up. Thanks, sry if its been reviewed already.

http://www.amsoil.com/StoreFront/mtg.aspx

 

I have been useing Amsoil products for 26 years and no complaints .I never use any other 2 cycle oil through my oil metering pump .My tranny and rearend have Amsoil as well. The motor does most of the time.

 

I actually am about to use the same product. Anyone use this exact one in trans and diff?????

 

This oil is fine for the tranny, but not the diff. In fact, IMHO it's better for the tranny than other synthetics owing to the fact that it's GL-4 and it's easier on the synchros chemically and mechanically.

In the diff you should use a true GL-5 oil.

Dave

 

i have that exact 75w90 in both my diff and tranny right now

 

GL-4 is not sufficient for the differential hypoid gear. I suggest you change it (diff oil) to GL-5.

Dave

 

so would it be better to run GL-5 oil in the tranny as well? bout to place an order for this: https://www.amsoil.com/storefront/Se...CategoryID=235

 

IMHO GL-4 in the tranny for the synchros' sake, and GL-5 or GL-6 in the diff for maximum protection of the hypoid. While I don't think it's a huge factor, the oils that perform best in the diff are a little too slick for the synchros in the tranny.

There are GL5s that are safe for the synchros and thus can be used in both the diff and tranny, but if you're buying from a company (Amsoil) that sells both and going to the trouble of changing the fluid it's kinda silly to compromise for no cash savings.

Dave