I've got an exhaust rattle on my 2006 limited 4wd. While in for it's 100mi tune up, I asked the dealer to take a look and they said my explorer has two in-line mufflers and that it was the "funny-shaped" muffler, the first one. And that since they would have to replace the whole exhaust, which is otherwise fine, I should go to a local garage and have the funny-shaped muffler replaced. Well, I finally crawled under it and the thing where they described it is sure enough funny looking - looks much more like a giant cat-convt than a muffler, does it have a name? Is it really just a muffler that I can swap out for something else? Finding parts for this thing is such a pain - nobody, not even the dealer, stocks even the air filters for it.

 

Coming off your exhaust manifolds will be the catalytic converter. It consists of 2 Pre-Converters (one one each exhaust manifold (Y-PIPE) and the the main converter. This pipe is then bolted to the muffler and intermediate pipe. Then the intermediate pipe is connected to the rear pipe which consists of a resonator muffler and tail pipe. I would sispect that your exhaust rattle is actually one or more of your converter heat shields rattling (welded corners broke) as this is a common problem. This can be resolved by putting a large adjustable strap around the shield(s) or use a steel banding kit.