98 e320 exhaust rattle

[Dave M]

I have come to really appreciate this mercedes site. It gave me the confidence and help to allow me to change the (12) spark plugs in my e320. I still have my mechanic do oil changes, though, so I can get his 32 point inspection. Anyway, I noticed an exhaust rattle, I assumed to be a heat shield causing the racket. Rather than go to my mechanic, I imposed upon a friend of mind to put the car on his lift and inspect the underside. After some gentle banging around it sounds like there's a baffle that is loose inside the muffler that is under the center of the car (the one just after the cat). It makes an awfull racket at idle at times, especially when you are next to a building (such as at a drive through window) but is unoticable at speed. Anybody else had this problem? Any suggestions for a fix that would not require a complete new "cat back" exhaust (it's all one piece). The exhaust system looks perfect on the outside, no corrosion or holes.
Thanks for any help.

Dave