Differential Oil
I did a search on differential oil and found that OT-OF-HERE contacted AAM and asked what weight oil to use on 07-06-2004. He was told 75W-90 pure synthetic with no additives. So... . I called them today and asked the same thing, talked to the same guy, Bob Dunn, and was told to use 75W-90 synthetic only. I didn't ask about additives, but I'm sure the answer would be the same. Looks like I will be ordering 75W-90 from Amsoil today.