I need to replace the diff fluid in my car. The guy at car quest didn't know for sure what kind of fluid I needed, so he said it's most likely 80W-90. I got a new 10 bolt gasket and 3 quarts of 80W-90. Is this the correct fluid?

 

Thats it!
Do you have a 10 bolt rear? The 9 bolt will look the same except for having 2 bolts and not 3 at the top. If you have the BW 9 bolt you will be retruning that gasket and getting some black RTV.
Aslo do you have a LSD or an open rear? I you have a Posi did you get modifier or at least oil with in already added?
And capacity is about 3.5 pints

 

It's a limited slip with 2.73 gears. I bought some posi-lube additive for limited slip so that the gears don't start sticking again (which is the reason why I'm putting in new fluid).

My dad counted the bolts and there were 10 he said and the computer at car quest said 10 bolt. Not a huge deal if I have to return it though.

 

From the 10-Bolt FAQ:

What Gear Oil Should I Use?
Standard 80-90 weight or a full synthetic, such as Mobil 1 75-90, along with a friction modifer (GM P/N 1052358) if the limited slip is an Auburn. A Gov-Lock or open/standard differential doesn’t require the additive. The rear holds approximately two quarts of gear oil.

https://www.thirdgen.org/forums/tran...-10-bolts.html

JamesC

 

I knew it would be in an easy spot but I couldn't find it.

Anyways changed the fluid today was pretty easy. Put on a new gasket and did one tube of this posi-lube for limited slip diff stuff and then the rest 80W-90. Worked great and my rear axle isn't making thuds anymore at stop lights