330d clonks when clutch released and vibrates on idle

my 330d vibrates on idle and makes a annoying vibarating sound from in the dash, i am a mechanic and the engine is sweet as a nut pulls like a train etc and the problem is only on idle. also when i go to reverse it makes a donk/ clunking sound which it also does sometimes when i release the cluth when changing gear, i dont have much knowledge of rear wheel drives i work on vans. it sounds like there is play in something like a diff mount or the prop shaft but i havnt got a clue, is any of these issues something that you can help me with please? thanks, wayne.

sounds like the dual-mass flywheel, I believe the give away sign is that it rattles when turning off the car. Does this happen to you?

Thanks for your reply, i have read back through my post and i was'nt very clear, im sorry about that. the two things that i have asked about are not connected at all the vibrations that i have on idle is a seperate issue haha, i have the vibration at idle that i spoke of but also a seperate issue which is the clunking donking sound when reversing and changing gear, the clonking sound seems to be coming from the back end of the car to me, i can feel and hear it behind me as i am driving, if you you have any ideas as to what any of these issues could be i would really appreciate your input as i dont have any knowledge of rear wheel drives or bmw diesels eigther, i work on vans so any pointers would be appreciated, thanks