The side-pipe exhaust system in my '97 XLT was giving me a fit with moans and groans from sympathetic vibrations driven by engine firing pulses. I tried every way from Sunday to work them out and finally arrived at this scheme that decouples the muffler and tail pipe from the engine exhaust Y-pipe.

The scheme employs a Walker 2-1/4" X 14" flexible pipe installed in place of the extension pipe between the Y-pipe and the muffler. An added hanger keeps the muffler from falling down.

The 2-1/4" pipe-ends on the flex pipe slide snuggly into the inside of the 2-1/2" exhaust pipes and a couple of 2-1/4" pipe clamps seal the deal.

The vibes are almost, but not quite, eliminated, but at least the annoyance factor is removed and things are tolerably quiet. And, since I'm not interested in super-high performance, the loss of approximately 10% of the pipe area through the flex pipe is of no concern.

 

Nice looking job!
Hope it fixes your problem..