Its the half-collar of metal that holds the exhaust in place right after the cat. converter on the 3rd gen. It has a metal rod attached to it that fits in the rubber grommet thing to reduce vibrations. Mine has rusted to piece's and after jacking up the truck, the exhaust is rattling where that collar should be holding the exhaust pipes together.

 

Are you wanting a part number? Because otherwise you seem to have answered your own question. Any muffler shop can weld you on a new support.

 

I need the part number because it is not welded on, i think it clamps on the pipe and the support rod attached to the rubber grommet is just another layer of protection

 

an exhaust shop will put on a new clamp, and then weld a rod with a bend in it to hook to rubber grommet, best bet... should be pretty cheap