Rear Diff Oil And Gasket

[Elexwiz]

Hi all. I'm new to this forum. I have a 2002 Silverado 1500HD that I bought in April. I'm changing the rear diff oil right now and had to stop when the ton of bricks hit my head that this is a limited slip. I bought Mobil-1 75w-90 LS fully synthetic. Does the LS stand for Limited Slip? I didn't think about limited-slip vs open diff when I got the oil. Will it work?

 

Second question, do I need any type of permatex or "gasket in a tube" or will the normal gasket I bought work? I ask because the existing gasket was a combo of each and I don't want to have to take the cover off again.

 

Thank you for your time,

Shawn

[RaddHazzard]

The oil you bought would be fine, the ls does mean what you thought. 1500Hd has the 14 bolt correct? Maybe 75 140 could be in order if you tow alot, otherwise what u have is fine. On the cover you should just use the gasket or permatex.

[Z45]

You do not have a limited slip rear differential. Limited slip differential are normally installed in cars, not GM trucks. All light duty trucks so equipped use a G80 mechanical locking differential.

 

Additives are not recommended in the G80 locking rear differential. I agree, the lube you used is OK.

[Elexwiz]

Thank you both for your help! Raddhazzard, why do you say the permatex OR the gasket? While I was waiting for some replies here I called a couple motor-heads and they said to use both. They said the permatex keeps the gasket in place and fills in any imperfections between the cover and the diff body. I'm just curious.

 

Elcamnio, thanks for setting me straight. I checked out the G80 locker and have some questions. How does the G80 rate compared to other aftermarket lockers that only lock when needed; like Aussie, Lock Right, and other Eaton lockers

 

Thanks,

Shawn

[jwhjr]

I just used the Permatex ultra grey in place of the paper gasket and haven't had a leak yet. It's been almost a year since I pulled the cover.

[Z45]

How does the G80 rate compared to other aftermarket lockers that only lock when needed; like Aussie, Lock Right, and other Eaton lockers

 

The G80 is an Eaton locker and only locks when needed. Once one wheel spins 100 rpm faster then the other it will engage. It will not engage over 20 mph.

 

Eaton G80 demo

 

I have owned many trucks with the G80 and IMO its a good rear axle but like everything it can be abused and blamed for things that are not its fault.

 

As for form-a-gasket, I would not use them on the differential cover. It comes with a gasket so a gasket it what should be used. Whats more, a gasket is simpler to work with. You put it on and your are done. With gasket in a tube you have to follow a certain time limits to cure/setup and before you can add lube and drive vehicle. No such limitation when a proper gasket is used. Also some can be chemically attacked by the lube you use making selection of the proper material important. Also, a gasket just make for a easier job of it. Clean the cover, lightly glue gasket to cover and install.

[Elexwiz]

Sweet! Thanks guys!