Got an 01 XJ with 200K miles. 4.0. I-6
When I go to take off a loud roaring sound comes from the exhaust and occasionally when in park I can see the exhaust flex up and down. Seems to stop after it hits 3rd gear. Muffler has a dent in it. Low rumbling happens when I come to a stop. Sounds don't happen ever in park or neutral. When I go over bumps after taking off it comes and goes as the Jeep bounces. Help

 

you may want to post a sound clip

 

I will a bit later. Muffler has a big dent in it if that matters.

 

might check motor and tranny mounts. when you rev up the motor or take off when driving the motor can move and when it does the exhaust goes with it, the dent has to be from that, when the motor mounts and tranny mounts are good everything stays firm and in place....just a thought