What type of Oil can be used in an H2 HUMMER Transfer Case and Front and Rear Differentials?

Do I have to use GM or can Other synthetic oils be used?

 

I used Royal Purple. It was really expensive but I heard it was awesome so thats what I used. When you go buy, just ask the parts place what the proper weight is and they will tell you. They have a computer that tells them what the manufacturer recommends.

 

I used Royal purple in my front diff.

 

Valvoline synthetic. No problems here.