Welcome to DF ! Glad to have you in a duramax from the darkside (cummins) ! As far as your tire grabbing, it sounds as though your locker is sticking. That will make the tires grab more in the turns. My 2008 did this when it was about a year old. Barked the tires backing up and turning and on garage concrete when it was wet. Turned out my rear end was bad and I put a new one in. Fixed the problem.
2008 GMC 2500HD LMM SLT CC SB 4x4 Z71
Buckstop front bumper, WARN M12000 winch, PIAA 520 ATP driving / PIAA 510 fog, Westin Platinum Series nerf bars, Pace Edwards Bedlocker tonneau cover, Cognito UCA leveling kit and HD Idler Pivot Assembly, Cognito Pitman and Idler steering braces, Bilstein 5100's, LT285/70R17 BFG AT KO tires, 17 x 9 XD Series Crank Wheels, 15% Tint Driver/Passenger windows, GM Tow Mirrors, DDM Tuning HID lights 6000K 35W