The muffler's resonator fell off. It was on the end of the muffler system past the converter and muffler near the end by the tail pipe. Is that needed? The sound hasn't changed.

 

My car does not have the resonator already but the tail pipe needs replacement. I have just shopped for the replacement part and located it at my local auto shop for about $22. It is a Walker tail pipe, part # 46550, described as OE fit; Resonator Substitute Pipe. My parts guy told me that the car might sound a little bit noisier without the resonator, but in my opinion, it is not at all, even with that gash (due to rust) on the pipe area that goes over the differential. Until I can get the part and have the time to fool with it, I just made a quick fix by using a mend kit to wrap around the 8" in gash. Works just fine.