Need help!! e90 rear knocking sound - videos included

Hi everyone!

My car started having a clicking/knocking sounds coming from the rear (I think it is the left side, but the sound resonates). At higher speeds I don't hear it but anything 40km/h and less, I hear a knocking sound when decreasing speed or accelarating slowly.

I just changed my rear differential a few months ago, so I doubt it is that.

My car in question


What could it be? I found videos on youtube and it sounds exactly like this:






Thanks!

sound like a rear tab bushing.... jack your car and check the wheel if it has free play