Noise from the area you refer to could be 1) The center support bearing rubber isolation has degraded and the driveshaft should be inspected for same and repaired/replaced straightaway. 2) A subframe/differential rubber isolation mount failure. 3) Bad rear shock mounts. I strongly recommend you seek out someone to put the car up in the air on a lift and inspect it for the unsafe issues that I have just presented, you might want to tow it to your BMW service provider to accomplish the inspection, be safe, do not take chances.

Answered by Dr. Hagerty (expert)
9,669 answers provided

Thank you for the info. I think it sounds more like a sharp electrical popping than frame /differential/shocks. But I will see my repair guy ASAP.
Again thank you.

Response from DrJon1
2 questions asked

My response may be a little over the top, but you can agree I'm sure, that noise can be different things to different people. Cyberspace has it's limitations.....

Answered by Dr. Hagerty (expert)
9,669 answers provided

Dr Hagerty,
Thank you again

Response from DrJon1
2 questions asked

You are very welcome.

Answered by Dr. Hagerty (expert)
9,669 answers provided