I'll try and explain as best as I can. My rear end doesn't work as it should, when I'm on an incline it doesn't want to work like it should. The front end pulls more and the rear doesn't seem to pull at all. So I jacked the front up off the ground on a jack and it moves the truck but when I go on a muddy incline only the front is working. I can't figure it out, any help would be helpful here. thanks

 

Do you have your center diff locked when on a muddy incline?
If not, only 1 wheel spinning(especially an unweighted front) would be pretty common.
With your center diff locked you would at least get 1 front a 1 rear wheel spinning.

 

yes diff is locked and the rear end is welded. I tried it locked and unlocked.

 

How much street driving do you do with that welded rear diff?