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