Originally Posted by mtbikbob
Or maybe the linkage is bent and not working correctly.
Get a friend to help you, get under your jeep on the drivers side and you should be able to see the linkage for the transfercase (under the skid plate from the front looking towards the rear), if your still not surem have your friend move the lever, it'll be the part that moves.
It is possble that something knocked part of it out, or bent it. If your friend is moving it you might see where it is having problems or be able to find a way to manually put it into 2wd for the time being.