OK. Before I start, let me state that this is not a slam at Full Traction, I love my lift. This problem is not thier fault, this is FYI should you encounter the same problem.
I had my lift installed about 4 weeks ago, and I really haven't wheeled it hard since. And I usually drive with the windows up and the radio blasting, so I did not hear this "Popping" sound untill 2 days ago.
The sound came from the passenger rear every time I hit a bump.
So I took it back to the install place (they have always treated me right and went the extra mile to help with this issue also).
So we put the JK up on the ramp and tried to reproduce the problem by bouncing the C**P out of it. Happend one time. so they re-tightened all the bolts to spec. checked for clearences and even tightened the rear bumper bolts, the sound seemed to be coming from the body area.
So with all the bolts tight I started to drive it off the ramp and "POP".
Ok back to square one, so as we are underneath and scratching our heads the shop forman comes over and pushes the JK from side to side, "POP POP POP". The only side to side link is the adjustable track bar, so with two, 3 hundred pound gorilas cranking on the track bar bolt we managed to get the bolt a little tighter on the passanger side.
Took the jk off the rack and No Pop. Drove it around over every bump I could find and No Pop. Great!!!!
So thanks to "Northern Tire and Wheel in Modesto" I no longer have the "Pop" sound.