on my 99 CC there is a clunking noise that comes from the rearend,it is more often when backing up and applying the brakes?,also when accelerating the drive shaft clunks against the floor,looked at the rear end and there is what looks to be a removable joint about 18 inches long,when spinning the driveshaft over it appears to not lock up all the time? appears the rear isnt locking as it should,seems to be slipping then catching?can i replace this coupling with another used one?there is not any vibrations present when driving car,otherwise seems to work fine.any help is appreciated,i was able to fix my brake lites as asked in earlier posts,found corroded wire? thanks Harvey B