OK so 1997 TJ, 2.5" Rancho susp lift, 33x1250 BF Mud Terrain on 15x9 MT Classic II rims. 120k miles. Ok here is the issue. Last winter it gets COLD as hell here in NH. I go outside it was -6, warm my Jeep up, (auto trans) put it in drive, push the gas pedal, engine revs, Jeep doesnt move! Moved maybe an inch or two but then rocked right back into starting postion. Yes i checked to see if there was ice on my brakes. none. So, I put it in 4wd, same thing it moves 1 to 3 inches, when I let off the gas it rolls back to start point. Finally after about 10 min of this I gas it hard, hear a loud POP, and I am off and running. No issues, ran fine, went through gears fine etc. A couple days later, cold as hell again and the same thing happened AGAIN. In total it happened 5 times. ANY IDEAS?? Im lost!