2008 GMC 2500 HD with major Transmission issues. Coming out of the mountains and stopped to help a family who had sunk his truck in 2 feet of snow. Helping him getting his truck out, there was a very large bang from underneath my truck. I was in 4 low getting him out, looked underneath and found that I snapped the from u joint coming out of the front of the transfer case. That's the easy part. He is the list of issues: No park reverse was park, now no reverse Truck runs Drives does shift automatically and manually on shifter Please help!!