2008 M3 rear differential noise (manual transmission)
I read all your comments and took the advice to change the differential oil just yesterday. As of today, the NOISE IS GONE. The technician indicated this is a known issue and there are many cases just like mine. He added three parts of the following diff oil: #83-22-2-282-583. I didn't have to pay for it even though they changed the original diff oil around 1,500 miles ago. Thanks for your advice!