Dalewhite

I found a couple of light dents in my stock 4.0 header pipe. I took the Jeep
to a muffler repair shop and the guy said my drive line had caused the dings.
I have a Rubicon trac bar and the axle seems to be centered so I can't figure
out how the axle/driveline gets displaced enough to hit the exhaust. Does
anyone have experience with this? Periodically I hear a loud snap from the
vicinity of the front end when running on dirt but so far my inspections have
not revealed the cause.
tia
dw