It's not always a loose part that triggers or allows DW to fully develop. My '97 TJ was only a year old when it had its only truly fully developed bouts of DW which I finally tracked down to one of my front wheels having lost its wheel balancing weights The TJ's solid front axle is susceptible to DW as are Ford, Dodge, and Chevy trucks and it often only takes an imperfectly balanced tire to trigger it.
But for older Jeeps, worn parts are often a major contributing reason DW is developing. Definitely do the dry steering test as described by Water Dpg above. Also get your tires PERFECTLY balanced. Not all tire shops will take the time to really get the tires balanced perfectly, they only get them to where they consider it good enough which is never good enough for a TJ.
And that "Cure" by Roughstuff is just a gimmick, it won't cure any actual problems in the TJ's front end and it won't even come close to helping with the subject of this thread, DW.