I have a 2002 Chevy Tahoe LT 4WD 5.3 engine size and the other day I got in my truck to go run some errands and when I put it in drive, my truck jerked then stopped. I put in reverse thinking I did something wrong then put it back in drive and my truck would not move. I put my truck in neutral and tried to push it back into the parking space and my truck would not move. I put some transmission fluid in it thinking it could be low on fluids and my truck will not move no more than an inch in drive or reverse. Now i'm hearing a cracking noises coming from under my truck almost like something is breaking. The gears shift and everything but my truck just will not move. Any help as to what may be wrong???