clunking noise and viberation

i have a clunking noise when letting up the clutch and at about 50-60mph i have a bad vibration wheel balance is ok as are the ujs on the prop shafts at about 65-70mph the vibration leaves again.....any ideas??

DMF failed.

i was hoping not to get that reply . i did notice a bit of give in the flywheel when doing the clutch last year.thank you datatek

datatek was correct the flywheel was bad so i changed it and put in a spare one i had. the spare felt a lot tighter than the one i took out but when i had it running it gets fits of viberating on tick over so i presume i fitted a flywheel as bad as the one i took out. so now i need a new flywheel and windscreen .

It's possible to weld up the DMF.