Hey guys, this september I bought a 2000 GLE w/ a motor swap w/ 60k on it. The car itself had 140k so i test drove it and it was smooth as silk. After a few days of buying it, I started hearing this noise from the inside of my car. It was like a squeeking sound every time i hit a bump and now, since its really cold in NY, i can even hear it when the car is warming up or if im idle on a hill somewhere. I can tell its coming from the exhaust because when I leave my car on and shake the muffler upwards, it makes the sound. I dont know what the hell it could be because all the hangers for it are perfectly welded and arent cracked or anything? Could anyone lend a helping hand? it would b very much appretiated.

 

take a look at the heat shield on your cat those often come loose and start rattling / squeaking , if its not that while your under the car shake your exhaust and it wont take long before you pinpoint the problem.
Hope this helps