Rear Clanking Sound

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http://rapidshare.de/files/14180021/2001-B...9-528i.wav.htmlLately I encountered a clanking sound from the rear of the car whenever I engage the D or R on the gearbox. I do hear the same thing whilst accelerating and decelerating at low speeds. (3 times clank). The workshop does not have clue except to change the propshaft to eliminate the problem which is an expensive solution IMHO. This is a problem plaquing Double Vanos E39 only at the moment so they say.I have recorded the sound and attached it above. It is recorded whilst the car is in stationary and engaging D to R and vice versa. Anybody have seen similar things and rectified it?Some of initial findings online1) Guibo?2) U Joint?3) CV Joint?4) Center Bearing?5) Coupling?Thanks in advance