Trd exhaust rattle

I installed the trd exhaust cat back on my 2010. I love the sound and I'm very pleased.
1 question: am I missing a gasket or something? It didn't come with one and there wasn't one there when I took it off. About 2200 rpm I get a rattle that I can't get to go away...
Any advice?

 

Not saying this is the problem, but it's a good place to start. There was some type of shitty clamp on the drivers side catalytic converter grass shield on my 2005. It busted loose and rattled its way away from the shield towards the rear of the truck.

I only heard it at idle, it drove me up the wall and I couldn't find the source. I thought it was the actual shield, but after the fifth time of testing either the grass shield or that foil heat shield bolted to the actual truck, I found the clamp. If its not that, others have said it was their grass shield, the heat shield or if its not that, not sure.

 

Thanks for the input.. I will look at that right now...