Gear Lube

[daniel3507]

wanting to drain the rear diff and replace it with Amsoil. slightly confused though as to what fluid to add though. 80w-90, or 75w-90? and how many quarts does it take for the 8.8?

 

[Rifleman]

Bearing tolerances and seals have varied some over the years. Knowing the year the 8.8 came out of would help. You would use whatever they specified for the vehicle it came out of.

 

[exbass94]

80w-90 and 75w-90 are almost the same thing. The 75w won't thicken up as much when it's freezing outside, but they're both a 90w (i.e. same thickness) above freezing.