: Rear Diff Fluid Amount

03-30-09, 10:56 AM
I'm changing my rear diff fluid this week to Amsoil myself after getting high qoutes for just labor..

Couple questions for those who have done it.

I have heard there is a gasket, and I have also heard to use silicone tube gasket...Which is better? If I use the gasket, do I also have to silicone the sides of it...I will be removing the whole cover for the drain.

Know the amount of fluid I will need for the cover removal drain( as opposed to the pry method at the bottom)?? I have heard anywhere from 2 quatrts to 6 quarts.


03-30-09, 11:30 AM
According to my GM Service Info DVD

* Front Drive Axle (8.25")
1.51 qt

* Front Drive Axle (9.25")
1.83 qt

* Rear Drive Axle (8.6")
2.15 qt

* Rear Drive Axle (9.5")
2.75 qt

* Rear Drive Axle (9.75")
3 qt

* Rear Drive Axle (10.5")
2.75 qt

I don't know how to tell which rear gear we have.

Here is what the Amsoil web site shows for our truck

NOTE: 2pints == 1quart

Differential, with 8.25 ring gear Front..........3.0 pints
Differential, with 9.25 ring gear Front..........3.7 pints
Differential, with 10.50 ring gear Rear..........5.5 pints
Differential, with 8.60 ring gear Rear..........4.3 pints
Differential, with 9.50 ring gear Rear..........5.5 pints
Differential, with 9.75 ring gear Rear..........6.0 pints

03-31-09, 12:07 AM
Wondering if there is any way to tell which diff's we have simply by the vin, OR by the sticker in the glove box.

I was actually thinking the same thing after looking up the same info on the amsoil website......HOW DO WE KNOW WHAT WE HAVE??

FYI, pretty easy to become a preferred member for amsoil and you get a pretty nice savings...I think 20-25% off the retail pricing.

03-31-09, 12:49 PM
Took me almost 6 quarts... it takes awhile for the fluid to settle down into it... so it may seem full, but after awhile, there is more room.

A how-to for the rear diff is here:


03-31-09, 07:47 PM
I just went to the dealer and they identified my gasket type by VIN. I bought the gasket and changed the fluid. The gasket was 10.00 but found it was 3-4.00 at auto zone/parts store. Be sure to have a good razor blade/scraper to remove the old gasket especialy if it is the original. It has a gasket sealer which takes a long time to remove. It took several hours to do the job and I just used the GASKET W/OUT any SEALER. It is doing fine. I will not say how many qts. due to so many variations. I wanted to use a replacement cover with a drain plug but it was 200.00++ and would have taken too long for it to be shipped. My diff. poored out when the plug was removed and filled it with valvoline synthetic. Hope this helps.