Rear Diff

TonyD · February 3, 2004

Hi all,

I am going to change the rear diff fluid this weekend to Mobi 1. I am just draining. In the summer I plan on taking the cover off and cleaning it. How many quarts do I need to buy? Its a 2000 gmc sierra 1500 4x4 34,000 miles, 3.73 gears. Thanks again

SilveradoWV · February 3, 2004

I think I had to buy 3 quarts but only use a little but out of the third quart. Someone else will know for sure!

REDZ-71 · February 4, 2004

The Service Manual states:

2.1 quarts for 8.5 inch Ring Gear (this is the axle that's in your truck A.K.A 10-bolt)

2.7 quarts for 9.5 inch Ring Gear

3.25 quarts for 10.5 inch Ring Gear

Fastener Tightening Specifications

8.5 inch Ring Gear:

Carrier Cover Bolts - 30 lb ft

Drain/Filler Plug - 45 lb ft

9.5 inch Ring Gear:

Carrier Cover Bolts - 30 lb ft

Drain/Filler Plug - 45 lb ft

Adjusting Nut - 50 lb ft

Brake Backing Plate - 105 lb ft

10.5 inch Ring Gear:

Axle Flange Bolt - 110 lb ft

Carrier Cover Bolts - 30 lb ft

Drain/Filler Plug - 45 lb ft

Also if you have the G80 option, you will need to purchase a limited slip axle additive from your local Chevy/GMC dealership. This will eliminate any nose associated with the engagement and disengagement of the locker.

TonyD · February 4, 2004

thanks for the info!

TonyD · February 5, 2004

One more question. Is there a substitute for the LS additive from GM? I have the G80 locker and saw some additive at Pep Boys. I wanted to put Mobil 1 in the rear but I am having troble finding it at the local stores.

REDZ-71 · February 8, 2004

I'm not sure if there is a substitute for the LS additive, and I would not want to experiment with the substitute since the one that GM sells is only $4.15 -to-$7.00 depending on the dealership.

Also, keep in mind that GM's Limited Slip Axle Lubricant Additive is specially compounded formulation for G80 locker. This additive modifies excess clutch plate friction and facilitates applying and releasing of clutch plates. It also reduces chatter and noise in the rear axle.

Here is the GM part # 1052358 (Limited Slip Axle Lubricant Additive) 4FL. OZ. bottle.

TonyD · February 8, 2004

Thanks all. I ended up buying Mobil 1 and went to the dealer for the 4oz additive. Someone told me i dont need to put the additive in because it is for pre 1999 trucks. I have the G80 locker option on my 2000 GMC Sierra 1500. Do I need the additive? Thanks..