Help !! Loud bang noise when making turns

[LScott]

I have a 2004 H2 with 25,000 miles, I've been experiencing a huge bang noise when I'm making sharp right or left turns going forward and the same when i'm backing up, it doesn't happen everytime, just occasionly. The noise and shake of the whole car will bring you out of your seat !! as if you had hit something hard !! The noise sounds like it is coming from a rear axle traveling all the way to the front end. It nevers does it on freeway or at high speeds.
Recently, I had to have the motor in the transfer case replaced because it would not shift out of 4wd Hi Lock to 4hi even though the dash light showed it had. Could these 2 problems be related ??? It's going back to the dealership for the 4th time - they are not fixing the problem !!!
I would appreciate everyones input.