When I first engage D in my car (particularly if it's cold) there's a loud thunk in the rear end right as I start to accelerate. Even if I'm quite gentle about it. It's been doing it for the 5 years I've owned it without getting any worse and the transmission operates normally otherwise so I'm not too worried about it. This is the only MB I've owned with ASR so I'm assuming it has something to do with that. But if anyone knows what's going on or has dealt with this before, I'd appreciate a light at the end of the tunnel.

Thanks