Show us a pic (side view) of your skid plate/ transmission mount.
Got a frame mount receiver hitch? My tail pipe clangs on that at odd times.
I’ve checked that. It’s not the problem. That would be a clunk, not a rattle unfortunately
That's what I was guessing. Why perplexed though? It's fairly common.
Oh, so there cat has a rattle but there is something else making noise too?
You talking about the drum for the brake?