Went wheeling today and everything was fine for awhile. Although it was a pita to get into 4L. After the hard part of the trail I shifted to 4H, it was also a PITA to get from 4L to 4H. As I was tooling along I pressed the gas and the engine revd but the Jeep did not move? I went into 2, 1, D, R, everything. And nothing happened. When I went into park I heard a grinding somewhere underneath and in front. When I was stalled so to speak it was a PITA to get from 4H, to regular 2WD, the shifter didn't want to budge. This happened twice. I was driving and then nothing. It seems as though the 4WD lever is pretty mushy in the 4H position, I suspect it merely came disengaged. Am I correct in assuming that the root of my problem is the shift linkage? Any advice or recommendations on how to remedy this?