I am having the same problem. However I have noticed it is slowly getting worse and I believe it is because of the condensation from the a/c pours on the exhaust crossover pipe after I park my truck. I know for fact that I haven’t hit anything. The top and bottom look like they are being beaten with a hammer. And I believe it’s because the cold water pouring in it is cooling it fast making it expand or contract. Has anyone had the issue with the condensation pouring on their pipes?