Our 50k mile 2013 GLK250 Bluetec (AWD) has recently started to clunk at low speeds - mostly turning right to the right. Vehicles drives great. No sensation whatsoever in the steering wheel. This kind of stuff is very difficult to ascertain location (you think it sounds in one place but it is actually elsewhere). It is not accel/decel related (not drivetrain load). Slow turning only. I personally think it is in the rear, right rear if I had to guess. I've done some searching with no luck. Any ideas?

Thanks in advance!

Filippo