Differential Oil - OK to use 75w/90???

[Achilles99]

Is it OK to use Amsoil synthetic diff oil that is 75w/90? I know that the stock fluid is 75/140...

 

[Steve 00RT/10]

I would use the Series 2000 75W-140 weight....as is recommended. You don't need any friction modifier. It's in there. Put the Series 2000 75W-90 in the transmission.

Steve

 

[Achilles99]

Cool, I was going to get some friction modifier for the Amsoil... didn't realize it was already in there. What exactly does the modifier do?

 

[Steve 00RT/10]

I'm no expert, but I think it has to do with alleviating gear and/or clutch chatter in limited slip rear ends.

Steve

 

[Tom F&L GoR]

The friction modifier keeps the clutches from a stick-slip situation; you'd notice it as one rear wheel winding up and hopping when in sharp turns at slow speeds (getting into a parking lot space.)