I have a 1987 560 sl and when I put the car in neutral while its running, it will make a banging noise. so I blocked the wheels and put it in neutral and looked under the car and saw the driveshaft rotating slightly one way then the other way making a clunking noise. It does not make any noise in drive or reverse or park, with or without the brakes applied. Anyone have any ideas - flex discs, center bearing, transmount? I'ld sure appreciate some ideas.