80W/90. I use Valvoline. https://www.autozone.com/greases-an...ormance-gear-oil-sae-80w-90-32-oz-/232566_0_0 BTW, the board is divided into various Forums. Each forum deals with a different part of the car, Engine, Transmission Brakes, ect. This question belongs in the Rear axle Forum, "Got Gears". One of the mods can move it over there.