I'm having the same problem. Sounds like a horrid metallic rattle when driving over even the smallest bumps.
I thought for sure it was my trailer hitch, but its not. So far I tried:
-Removing trailer hitch
-Shimming the exhaust tip (thinking it may have been banging against the bedside)
-Torquing down the catback exhaust bolts
-Shaking and banging every segment of the exhaust to see if a hanger or something is making contact
-groping every inch of her underside (ya I went there) to find anything loose
-Even put my dad in the bed of the truck while I drove it to try to help locate the rattle (couldn't)
The only thing loose is what looks like a brake line next to the leaf.
I'm guessing maybe the leafs have had it?
As soon as my forged offroad rebuilt shocks get in I'll get those in and check torque on the leaf spring bolts. See if it goes away. Iunno
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