You’re the man!I would climb under there and look/feel around. It's purely a mechanical linkage. If I remember correctly, it's just a rod that connects to the shift lever, then it goes back, over the top of the transfer case, where it connects to to an arm on the transfer case. There should be a bit of rotational slop. If there isn't, something's seized.
Here's the story, can't shift to 4low....have pulled on that lever with everything I've got. Freed the shifter by removing the 4 bolts that attache it to the transmission housing. Was able to determine that the arm pivots and the pin on the front portion of the linkage right under the shifter...forum.ih8mud.com
That's going to be fun...
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