Loose track bar bolts (on the axle end) usually "pop" during left hand turns. My TJ has done it before, and both my old XJ and my buddy's XJ have done that too.
Torquing the bolt back to spec fixed it, but after it recurred I finally put in a larger bolt and it quit for good.
You probably will also want to check the track bar nut on the frame bracket while you're at it.
EDIT: Glad you got it. I started my reply while your last post was on its way - got distracted and then hit the post button w/o rechacking the thread, so.... nevermind.
2003 Bright Silver Rubicon
285/70/17 Goodyear Kevlar MT/R's, OME, DIY bumpers/roll cage upgrades,
Champion beadlocks, 33Eng BellyUp w/CV shaft, JKS BL&MML