I was thinking of puting mobil 1 tranny fluid and mobil 1 gear lube in front and rear diff, and transfer case? would this be the right thing to do?

 

A lot of guys have NOT been using synthetic in the tranny. There are reports of it leading to problems in the higher milage days. However, in the front and rear diff, most of us that have changed one or the other use Mobil 1 (I do), Reline or Royal Purple seem to be the most used. Just make sure you use the GM posi aditive if you have one.