Rattle sound

[mikelmco]

I have a rattle that sounds like it is coming from under the car when I have the tranny in drive or reverse. Cannot locate the sound. Any ideas?

[mturanny]

i had the same problem. It was my catalyic converters. They went bad. Have your mechanic put it on a lift and shake them. You only hear it when you drive it. Hopefully it's only one of them. It can cost about $1000-$1500 to have each replaced. I have a 2003 clk 320 with 66K miles.