Does the front axle differential use the same 80/90 weight gear oil as the rear axle or is the a different grade because of the 4 wheel drive.

Thanks

Same.

Dodge was having some problems with these rear ends. Their solution was to use synthetic in all of them from the factory since 2003. You don't have to use it, but it is better.

Like you said, the rearend. And that was only for the crappy LSD rearend. However, He was asking about the front.

I'm not sure if they included the front on the TSB. My daughter has the same truck I do. When we did a fluid change hers had synthetic in both, mine only had it in the rear.

Do not use synthetic gear lube!The problem with synthetic gear lube is that is too hard on ring and pinions.I know of three rear ends going out due to synthetic gear lube.My father's friend Rich has seen it,replaced gear sets due to use of synthetic gear lube and one gear set was down to the size of a pencil tip.Synthetic gear lube is also not recomended for Dteroit Lockers.