Noise from rear cab/bed area?
 

Whenever I hit a bump in my 2012 F250 Supercab I hear a noise coming from either the rear of the cab and/or the bed area like something is loose and banging and squeaking as if a body panel isn't fully secured. However, I've poked around quite a bit back there and haven't found anything that seems obviously loose. Could it be something on the underside like a skid plate or heat shield? The truck did come with an aftermarket back rack, but that seems pretty secure as well.

Spare tire?

are your rails attaching the truck bed to the frame rotted out?
they come pre-rusted from the factory, so...

I'll check this but I rolled around underneath the truck quite a bit prior to purchasing it and it was remarkably clean. It's an XL work package that was owned by a utility company but it doesn't seem to have ever plowed. It did see salt as the company was based in Massachusetts.

It could be a thousand things.. Spare tire was a good one.. Bed bolts, U-Bolts, Exhaust, etc etc

Get it on a lift and check it out..

Check between the bed and cab for foreign objects. I had a piece of wood fall in between that was causing some rattles...

A rubber mallet banging around under the truck might cause the noise.

No, you likely don't have one banging around under there at the moment, but using one is a good way to make things vibrate without breaking them. As I said, it might cause the noise.

This. I stood in the bed of the truck today and gave the back rack a good whack with my fists and was able to replicate the noise. The rack is mounted pretty securely, but it vibrates just enough on bumpy roads. I'd like to find a way to quiet it as it is kind of annoying-maybe some rubber washers for the mounting bolts?