One problem related to steering gear box shaft pitman has been reported for the 1998 Jeep Grand Cherokee. The most recently reported issues are listed below.
I hit a small bump and the front end started to shake very intensely. I could feel it in the steering wheel. To stop I had to step hard on the brake, and I was in a center lane of traffic. It was a very dangerous maneuver. Since the first time it happened it has gotten progressively more frequent, even though I have tried a variety of strategies to repair this problem: new tires, multiple alignments, new shocks (twice), replaced track bar, replace sway bar bushings, replaced steering gear box and pitman arm. I have had several mechanics look at it. It is very frustrating. The car is old, I understand that, but there is no logical reason it can not be made safe. Yet it is not safe, despite my ongoing efforts to make it so. I have not yet given up, because of course I can't sell it. If I can't fix it, I might as well junk it, even though the motor runs great.