OT: How to find out type of GMC Yukon axle?

[SteveF]

So, a 2001 GMC Yukon Denali XL 1500 with 4 WD. Apparently the rear brake pads are different depending upon whether this has the limited slip rear axle or not. The Chilton's manual is of no help. How can I find out if this is a limited slip axle? The Chilton's manual also vaguely says that if I am changing the gear oil that a limited slip axle MAY need a lubricant additive.

Any mechanics here know how to find this information?

Thanks.

[Michael Edwards]

The info from the tag on the differential and some interwebs searching should get you there.


https://www.differentials.com/techni...dentification/

[SteveF]

Thanks. After another hour of searching I've learned that there is a Service Parts Identification sticker under all that paperwork in the glove box. With an RPO decoder I have the 3.73 Limited Slip and it's not supposed to have any additive added.

As Rosanne Rosanadana used to say "Never mind".

Steve

[Greg_B]

Good you found it, a lot of those stickers get worn/damaged over time. Could have also run the VIN through an online decoder also. Might have shown up.

[Joe Rogers]

A call to any GMC parts department would get you all the options and the descriptions. They are linked into the GM database through the parts catalog computer. The additive is only to bandaid customer concerns as to noises etc.
Joe

[Willy]

Joe, I had always thought that the additive was a supplemental friction modifier added to a conventional gear oil in order to eliminate the slip/stick in the clutch pack prevalent in some limited slip/positraction rear axles. This can lead to the noise associated with that type of rear axle when negotiating a tight radius turn due to the clutches grabbing and releasing.

[Captain K]

Jack up the rear axle. Turn one wheel by hand, if the other wheel turns the opposite way it’s not limited slip. If you can’t turn the wheel without putting it in neutral then it’s limited slip.

[kendall]

Joe, I had always thought that the additive was a supplemental friction modifier added to a conventional gear oil in order to eliminate the slip/stick in the clutch pack prevalent in some limited slip/positraction rear axles. This can lead to the noise associated with that type of rear axle when negotiating a tight radius turn due to the clutches grabbing and releasing.

That's exactly what it does, it increases the slip in the clutch type differentials. I never use the stuff in my vehicles, I prefer a nice solid grip, and it seems that they last longer without it.
I think some GM LS diffs are the geared type