Part of this question belongs in other forums but;

I went looking for a full synthetic motor oil (15w40)and was told none of the major lube refiners make it. Whats up with that?

Second; can I use the 75W90 synthetic in my front diff, the same lube as the rear diff.

Third; is there another lube refiner that makes the lube for the automatic transfer case, (Autotrak II).

Forth and final; can I get synthetic Dex 3 for my Allison.

:help: :help: :help:

DUK

Petro Canada makes a 5w40 that I use all year round. It's good for the cold winter starts, and works fine in the summer too.

Yes, you can run 75W90 Syn in both diffs.

most synthetics i have found are 5w40

Amsoil full synthetic 15W-40 heavy duty diesel oil. They also have synthetic Dex III, Axles fluids, etc. Mike