Gear Oil - GM Synthetic 75w-90

[jpoole]

Alright, found out it is an Auburn unit. So no synthetic gear oil or friction modifier? Also, which is better the eaton or the auburn?

 

[pontiacgp]

From Auburn...but if it were me I'd use synthetic with no additive. I have amsoil in my Eaton and some say along with the instructions from Eaton you are not supposed to run a synthetic oil but currently GM runs synthetic in all their posi rears. With a posi rear chattering will cause premature wear and the additive can be added to sure that. If you have too much additive the posi will slip but that can be cured with a new oil with less additive. The other thing if I ruin the clutch packs in mt Eaton I can replace the clutch packs, the Auburn with it's cones are not rebuildable.

-IMPORTANT LUBRICANT NOTEThe
Auburn Gear limited-slip differential design has been extensively tested with high quality
non-synthetic 80W90 hypoid oils treated with GM or Ford friction additives (3 oz. of additive
will treat 1 quart of oil). To avoid differential clutch chatter (noise) and for optimum
performance, use the oil and additive described above. Use of other additive and oil types may
cause differential clutch chatter.
! Ford Part Number: C8A219B546A
! GM Part Number: 1052358