After some investigation, I found the source of my horrible rattle/metal-on-metal noise. The heat shield around my cat has broken a weld, and is rattling against the cat itself.

So the question is, how to remedy this: My first thought was to just cut it off, but with the operating temperatures of a catalytic converter, is that a smart decision? I bent the shield a little to try to cut down on the frequency of the rattle, but something needs to be done about it. I have a torch at work, which can melt steel, so I'm thinking I may just try to fuse it together that way.

But, when that method fails, what should I do to fix it?

Also:

 

Hose clamp could hold it.

 

Wife's Tracker did the same thing. I wrapped it with coat hanger, and twisted the ends together. Has held fine for months. Ghetto, but it works.

 

Big *** hose clamps purchased. Why didn't I think of that?

 

Method has worked for me in the past but usually around where the shield gets smaller near the pipe inlet and outlet. I would say don't take it off. It gets hot enough inside the car from the trans warming let alone an un-shielded cat.

 

Apparently bending the hell out of the heat shield has fixed the issue....... After a few more months of Pittsburgh roads, I'm sure the rest of the welds will break and it'll just fall off.