kinabub

What is the current equivalent of GM 3758790 or 3758791?

The rear ended has been cleaned and rebuilt. I want to insure that I use the correct lubricant

Frankie the Fink

Amsoil makes friction modifier (Slip Lock) but why not go to your dealer and get the GM product - that's what I did... ?

Sullyvette

I had an issue with my rear differential, I added 10-4034 Dexron LS gear oil 75W-90.
Corrected the clunking issue, Thanks to the advice of Frankie and others. Good Luck, Sully

SWCDuke

It's not clear to me if you're talking about the oil or limited slip additive, but any API certified 80W-90 GL-5 oil is correct and brand makes no difference.

The limited slip (Positraction) additive is available from NAPA - NCB4285V, 4-0z.bottle.

All manufacturers of clutch type LSDs use the same additive. You don't have to buy it from a GM dealer.

Duke

GTOguy

I agree. Generic works fine. Had a GM diff rebuilt by a pro 27 years ago and he recommended using Ford LSD additive instead of the GM stuff. Personal preference. Just remember, don't overdo it. Too much additive and the clutches will slip excessively. Just enough so it doesn't chatter...(usually one bottle).