I hate noises. They are always difficult to pin point and in the cabin they could be coming from anywhere but sounds like they are coming from somewhere different.
If it coming from the rear, you'll have to bite the bullet and get under it and check everything. Every bolt, nut & whatever else is under there. Shouldn't take to long, just lift it up and touch everything with your hand. If something is loose where your finger can move it or turn it, well fix it.
If you still don't find the noise you will need to start looking at thing one by one; Brakes, covers, exhaust, diff, suspension.