I bought a 2021 Silverado custom. I’m hearing the clunking noise from the mid to back of the truck. Almost like something is rolling around in the bed of the truck. I notice it more on uneven surfaces and in reverse. Really bad pulling into and backing out of my driveway. I took it to my dealer and left it for 7 days. They couldn’t find anything. I drove with the mechanic and pointed out the noise. He says it’s the suspension settling in. He says bring it back if it gets worse, nothing they can do at this point. It’s is a very annoying sound. I wouldn’t have bought this truck if I would’ve heard this on the test drive.