I had the same problem with mine (94 XJ). After looking closely at the steering shaft I noticed that there was movement between the upper "hub" (below the u joint) that connects to the steering column shaft and the main shaft. It seems that there's a rubber insulation sleeve that's vulcanized to the metal and that part had come un-vulcanized and was moving between 2 tabs. These tabs appear to be there only for safety in the event that the rubber vulcanizing fails... which is what happened in my case. Hope you get the drift of what I'm saying. I tried to take a picture but couldn't get a decent shot. I replaced the shaft and end of dead spot. BTW, I replaced the steering box before I found out what the problem was. Most were saying to adjust the play by tightening the adjustment screw. It didn't work for me.