Rear Differential fluid....Which one?

[swathdiver]

That didn't answer the question.

Post #9 answers #7 and #8, post #2 answers #1.

 

[HiHoeSilver]

Post #9 answers #7 and #8, post #2 answers #1.

Posts #7&8 didn't have questions in them ..... Lol

 

[swathdiver]

Semantics, and should have included #6 too! LOL

That post settles the debate and confusion.

 

[HiHoeSilver]

Semantics, and should have included #6 too! LOL

That post settles the debate and confusion.

TBD

 

[Rocket Man]

The factory differential fluid, 89021677/10-4016 includes the limited slip additive. Stick with the manuals and not the foolishness of the internet. In the old days, we had to add a bottle or two of factory limited slip additive to the differential lube to keep the clutches on the G80 from chattering. Now it is included.

Post #9 answers #7 and #8, post #2 answers #1.

From my manual (and I have the G80 rear as well as the front differential): "Front and Rear Axle:
SAE 75W -90 Synthetic Axle lubricant (GM Part No 12378261) or equivalent meeting GM Spec 9986115". I used Mobli 1 75W-90 synthetic and read that it is compatible with the spec. but there is still much confusion out there. I gather that the additive is either included in the synthetics or there is some other reason the synthetic works. But I did read a LOT on it and all I ended up with was a headache and the greater assertion that synthetics work, specifically either Mobil 1 or Royal Purple.

 

[swathdiver]

The factory synthetic fluid has included the additive for near twenty years if not longer.

 

[Rocket Man]

Who the hell wants to buy from the dealership? There isn't a damn thing I'll buy from any around here unless it's an emergency. I had to buy a dipstick tube for my engine when I was doing headers and they charged me $10 OVER list price so I went home and ordered the same damn part from Amazon Prime for $20 less and when it came I returned the Amazon one to the dealer and they still charged me $10 to restock it. Thieves.