Differential fluid thoughts/recommendations...

I am not a fanboy of amsoil in any way, shape, or form. But from my racing days, which wasn't all that long ago, Amsoil gear lube is fantastic lube. Id use it in both diffs, along with the bigger cover.

I use no other amsoil products. Not saying they are bad OR good, just saying I know from experience in super extreme conditions, the gear lube is great, where other brands have failed for me and wrecked stuff.