One problem related to universal joint has been reported for the 1998 Jeep Wrangler. The most recently reported issues are listed below.
Rear drive shaft sheared in two at a weld joint located between the shaft main tube body and universal joint part. The failure appears to be associated with an improper weld seam (weld on apparently a third of the circumference of the shaft tube appears not to have been completed). I don't know if the welding process was done manually or by machine and if by machine how many other shafts are similarly affected. I will mail a more complete copy of a write-up of the incident as well as photographs (I sent Chrysler. I contacted Chrysler and they have not followed up on the incident (other than a voice mail acknowledging receipt of a letter from me and they would look into the matter. That has been close to 5 months of no response.