I have a 96 Grand Cherokee 124K miles. Fluid full. It just stopped in the middle of the road would not move in any gear. I had to have it towed home. While trying things I've noticed that it will move while cold but in a bit when its warmed up same thing nothing will move. Also while trying other things. If you put shift into "N" start engine it will move in the either in "R" or "F" but only that one time when you try and change to another gear or direction nothing will work. There is a slight faint clicking sound. Please help.
JeepMan1ahttp://www.automotiveforums.com/vbulletin/images/icons/icon5.gif

That sounds like what mine did about 2 months ago. I had to get my tranny rebuilt and it cost $1600. Hopefully yours isnt the same.