I have the same problem. The back of the tire is moving more than the front of the tire in the side-to-side movement. In this case, the knuckle is pivoting on the steering links, and allowing the axle to move back and forth under the vehicle. The problem here is most likely in the trackbar system.

 

What is the best trac bar out there? I was looking into the one from Iron Man 4x4. Currently I am running an adjustable system from rusty's its got an oem tre on the frame end. Everyone keeps telling me to look into my trac bar but my bushings are good. I just replaced the tre. The bar is not bent and the axle is perfectly centered under the jeep. All of the bolts are torques to spec.

Is there something else that I'm missing?

 

I have Rusty's heavy duty adjustable track bar. I haven't had any issues with it. Been running it for a few years. You may need to replace the bushings. New bushings always seem to make things better. It's kinda like gettin laid.