Chrysler decided to use 14 mm bolts for the front trackbar on 07-12 Jeep JKs even though the stock bracket holes and the trackbar end bolt sleeve holes are 9/16".
This is a common source of Death Wobble for 07-12 Jeep JKs because if the stock bolts are not correctly torqued and periodically retorqued, the looseness or play of the 14 mm bolts in the 9/16" bracket holes ends up ovaling/wallowing the holes out--allowing even more play/looseness.
When the bolts are not sufficiently torqued and the bolt holes are ovaled/wallowed out, and the suspension hits a pothole, railroad track, or some other road imperfection, the front end suspension and steering can get thrown into a very violent harmonic type resonance that can end up damaging the rest of the front end components (ball joints, drag link ends, tie rod ends, unit bearings, front upper axle side control arm bushings, etc.).
Death wobble is so violent that it can crack or tear off stock trackbar brackets and welds.
Death wobble requires coming almost to a complete stop to get the harmonic resonance/vibration/wobble to stop. It is dangerous because the driver can lose control of their vehicle.
It is vital to stop driving a vehicle that has had even one episode of death wobble and immediately diagnose and fix the source(s) of the problem.
Death wobble is relatively simple to diagnose and fix through a series of component inspections.
I have posted write-ups on several jeep related forums about how to diagnose and fix death wobble. Generally, post #1 explains DW, and post #2 gives an inspection checklist.