Thought I would give an update here. Got a deal on a complete cat back exhaust from Gibson. So I pulled the tail pipe off and then the muffler. The muffler was not loose on the inside but the converters were. I fixed that and started the truck with no muffler. It was loud... I was in the shop across the yard with the doors shut and the kids could hear it in the house. I didnt notice the rattling sound so I thought all was well. I installed the new Gibson muffler and reused my original tail pipe, because it was one piece and had the heat shields for the spare tire.

It sounds great! But the noise is still there...