Here's what happened. I was on a boat ramp covered in snow (hard packed). The truck was in AWD and wouldn't move up the ramp. My right front wheel started slipping and spinning fast while the truck just sat still. I then put the truck into 4Wheel Low (while in Neutral) and I felt it engage. Then tried again to go up the ramp and got the same result (only the front right wheel spun fast) and the truck didn't move. No other wheels attempted to power the truck forward. Any ideas? Oh, one other thing..probably a coincidence.... I am getting a moaning from the right front at speeds above 30 mph. I'm thinking it's a wheel bearing.