clunking noise come from rear when i go over mild bumps

[Vetruck]

Check your spare tire compartment for loose tools/ jack/ lug wrench.

A little funny story I'll share along these lines: I recently helped a friend troubleshoot a pulsating thumping noise in his rear suspension of his BMW X5. I sat in the back seat and once he was over 60mph it would start making the noise. I immediately with a smile on my face told him to get off the freeway and pull over. I get out, reach under the back of the car and find some windage plastic panels and start thumping one mimicing the sound- he looks and says that's it. It was a panel flapping in the wind under the car with a fastener broken. A ziptie quickly fixed what he thought was the air ride system rubbing on a tire or something when the system lowered automatically at speed.