Klunky sound after replacing exhaust manifold

Hi all,

I've recently replaced my exhaust manifold. A great thanks to all of you that assisted with advise and what more! It worked out great and I love the way my jeep sounds!

However, since after the repair I now sometime hear a klunky sound from the back. I am no native English speaker and surely 'klunky' is not a real word, but that's how it sounds. Right after the repair I first heard this but since I was carrying around most of my tools in the back for a while the sound was easily explained as tools bouncing up and down on the floor of the trunk. So I was not too worried. However when I took the tools out I still sometimes here it. It's new (I've not heard that before the repair), and fairly rare. It mostly occurs when I idle or accelerating on an incline (hill-up). But it is not very consistent.

My guess is that I maybe changed the alignment of the exhaust a little so that it hits the car, but then I would expect the sound to be coming from the front (pan). There seems enough clearance there though. In the rear I did not change anything, and the only thing I can come up with is the cat. But i don't know what sort of sound a failing cat makes. Can that be something like what I described? Or is the cat hitting the car somehow?

What do you think? How do I check/verify what's causing it?

Thanks

Tim

Your first guess is probably correct, The tail pipe will rattle against the side of the gas tank and or the leaf springs and shackles. Check there. It happens mostly at certain frequencies caused during acceration and deacceleration.

Ok, I found the source of the sound. The gas tank has these wide rims (in the middle where the sheets of metal are pressed/put together) and it hits the exhaust pipe (there is some visible wear on the exhaust pipe also). Very likely this is the souce of the noise. Now, question, would it hurt any if I were just to bent that rim (with seems just two layers of pressed sheet metal) a little up- or downward?

Thanks!

Tim