Went out wheelin today, I could feel that my 4wd wasnt working cause of the slippage. I put it in 2wd and backed down a bit, then put it back in 4hi for another go. Before I could go anywhere, the TC started grinding real bad. I figured it was a fluke, out it in 2wd then 4wd and everything was fine for a few hill climbs. stopped at the bottom of one to reposition, as soon as I went from reverse to drive it started grinding again. After much debated my buddy told me to try it in 4lo. I did and it was fine, ran fine and was able to get back to pavement that way. no problems and very tight. What is up with my 4hi?

 

Sounds like the lever is out of adjustment or the bushings or tranny mount could be wasted.
Also check the mounting of the lever to floor itself. I've seen the sheet metal screws in those strip out of the floor.