11 replies to this topic

[Dave in Mpls]

After reading several posts on the topic, I'm now more confused than ever!!

I have a 2002 'Burb LT with an RPO code G80. According to the 2002 RPOs on this site, the 2002 G80 is "Axel Positraction Limited Slip", whereas the 2003 G80 is listed as "Differential, Locking, Heavy-duty, rear".

My question - is the 2002 G80 a locking or limited slip differential and, more importantly, can I run Mobil 1 gear lube in it, and do I need to run the additive?

Thanks!

[Jacqson]

After reading several posts on the topic, I'm now more confused than ever!!

I have a 2002 'Burb LT with an RPO code G80.  According to the 2002 RPOs on this site, the 2002 G80 is "Axel Positraction Limited Slip", whereas the 2003 G80 is listed as "Differential, Locking, Heavy-duty, rear".

My question - is the 2002 G80 a locking or limited slip differential and, more importantly, can I run Mobil 1 gear lube in it, and do I need to run the additive?

Thanks!

<{POST_SNAPBACK}>

The G80 is a locking differential, and is the Mobil 1 you want to use a synthetic or regular gear oil? The recommended oil for the rear axle according to the GM Service Manual for your truck is a 75w-90 Synthetic (GM part#12378261 for the U.S. and Part#10953455 for Canada) or equivalent meeting GM specification No. 9986115. The Service Manual makes no mention of Limited Slip additive so I would say you do not need it unless you get chattering from the rear.

[asilverblazer]

At first it will allow a 100rpm difference in each wheels speed (about), limited slip, at which point the locking mechanism will be activated, fully locking the rear wheels together with no difference in wheel speed allowed between them.

[Butch 02 Denali]

The Eaton G80 is both a limited slip and a locker!

GM recommended synthetic lube has the additive in it already, that is why they say not to add any!

http://automotive.ea...ockingdiff.html

Edited by Butch 02 Denali, 31 March 2005 - 09:45 AM.

[Kurt_T]

I also have an issue cause i have an 2001 2500HD with the 8.1 and 3.73s and my sticker in the glove box also says G80 but it says that the G80 is a Limited Slip when i look it up on the Code Chart? which is it really limited slip or locker?

[RyanbabZ71]

G80 = Differential Heavy Duty Automatic Locking Rear

This is what is on my 2000 Silverado, 2008 Tahoe, and 2010 Silverado build sheets

[Kurt_T]

so then yeah i do have a Rear Locker? is what youre trying to say

[ChevyTech77]

so then yeah i do have a Rear Locker? is what youre trying to say

Correct. All G80 RPO code trucks, with the exception of QS, are Eaton locking differentials.
99 to current take 75w90 synthetic gear oil with no limited slip additive.

[RyanbabZ71]

so then yeah i do have a Rear Locker? is what youre trying to say

Its not what I was trying to say its what was stated.

[Kurt_T]

so then yeah i do have a Rear Locker? is what youre trying to say

Correct. All G80 RPO code trucks, with the exception of QS, are Eaton locking differentials.
99 to current take 75w90 synthetic gear oil with no limited slip additive.

thanks! did not know that, very helpful!

[snakedoctor]

See video...

[johnnyquick]

and then read the comments these rear ends are notorious for blowing up when used as they are intended.

See video...