Truck is pulling hard to the right 2003 GMC Sierra 1500 4x4

[SevenNumbers]

I have a 2003 GMC Sierra 1500 4x4.

 

The problem I am having is that my truck is pulling to the right very hard.

 

After my back tires spin, for any resson or I hit a pothole, the truck pulls to the right very hard. If I try to make a left its ver hard and my tires start to squeal.

 

What ever is doing it, releases after a hard right turn (example: if I'm driving north and turn east.) is made and a single loud click is heard from the rear, then my steering is fine.

 

I have changed the front differential, the transfer case and had an alignment and no change. Please help...

[gmtech4]

Sounds like the rear diff bushings ?

 

Have the rear of truck looked at

[catstoy]

sounds like the locker in the rear axle is not releasing has it been serviced and are the tire sizes the same on both sides hope this helps

[SevenNumbers]

As far as I know the rear axle has not been serviced but I will have it checked this weekend along with the rear bushings and reply back with the results. as for the tires, all four are the same.