Hi, I have a good running 97 jeep cherokee. When idling or pulling out, the muffler will vibrate pretty bad and I can feel it in the cab. I actually got a mechanics stethoscope, and by measuring vibrations with it, I'm pretty sure its the muffler, not the cat. My mounts all seem to be pretty solid, and nothing is rattling or touching anything, and I even replaced the busing and clamp on one of them to get a tighter overall mount. I would just write it off as a jeep thing but it's definitely gotten worse and I wanted to see if anyone had any ideas. The muffler is probably 5 years old, cat is 10+ years old, upper and lower pipes are 2-3 years old. Rebuilt 4.0 with auto tranny 1997.

Also, it's definitely coming from the radiator, all my engine and tranny mounts are new, and its easy to feel the exhaust system and observe the same rattling sensation as in cab.

 

How's the mount on the crossmember ?? That would be my first guess as a resonating problem with the exhaust system...