Okay.. Here is the story. I've been trying to pinpoint this weird rear noise for the longest time in my car. The noise can be described as a metal creaking/squeaking sound whenever I take off from a complete stop going either forward or reverse. Also, during driving, if I let off the gas and coast I hear the noises too. I took the back seat out of my car and folded the rear seats down so I could really listen to it. One thing I've noticed is that the noise goes away if the car has a full load (people/luggage). Anybody experience anything like this? I have replaced the RSMs, shocks, and diff bolts in the process of trying to rid the car of this noise. I was thinking about trying the RTABs next since the noise seems to be coming from right on top of the area from inside the car. Do worn RTABs make noise when they are worn? The noise seems to be coming mostly from the passenger rear side. My car has 97K miles on it and has been driven hard at times. If anybody has any insight, I would appreciate it. I think I'm getting close to finally finding the culprit. Thanks.

Definitely the RTABs. My RTABs were recently replaced but the mechanic didn't bolt it tight enough to 81 ft/lbs for the bracket that holds to the trailing arm. After couple of weeks driving, I hear metal banging/squeaking noise from underneath the car in the rear when I take off from a stop and when I coast. I took my car into the shop and lo and behold, the bracket is loose!! They tighten it down to 81 ft/lbs and now the noise is gone and my rear end feels stiffer. I can feel more torque xfer to the wheels when I go WOT.

I'll have to take a look. I hope the problem is the RTABs. I think I'm going to replace them with the stock ones unless there are better options. My car is mainly for street and rarely sees track days.

Could it be the Rear subframe mount/dampener? I saw a thread where someones was bad. It looked like it was just in front of the differential on the right hand side. Has anyone ever replaced this rubber bushing?

I've checked all the differential and differential carrier bolts. They are tights. Hopefully it is the RTABs. If not, I have no clue.

I had similar noise on my 94 325i and it was "support for shock absorber", the metal one, welded to the chassis. It can be bought as separate part and it was about 10 USD.

You can inspect it by removing entire rear shock absorber, together with RSM. Mine was all corroded and nearly the absorber went through metal.