Serious Drivetrain Clunk
 

My 87 560SL has had a serious clunk in the drivetrain whenever I shift from neutral to drive or reverse. Nothing happens for about a second, then it bangs hard. Also, when the transmission downshifts as the car is slowing down, I get the same delay and clunk when I step on the gas. There is no driveshaft vibration or any other symptoms that I'm aware of.
Anybody run into this before?

Max

I would speculate that you either have a very worn out front flex disc and / or broken differential mounts.

In the case of a very worn out flex disk, you want to get this looked at immediately.

If it breaks when you are on the road, you will do serious damage to the underside of your car, as it will take out your center support bearing and the drive shaft will bang against the drive shaft tunnel. Your airbag, if you have one, will also explode as the sensor for the airbag is right above the drive shaft.

I tend not to think its either the flex disc or the differential mounts, but I could be wrong. The reason I think this is that when I shift into gear nothing seems to happen in the transmission itself for a second or so, then it bangs into gear. Also, there is no driveshaft vibration, and the car seems to track perfectly straight. I'm afraid it might be the transmission (already had the transmission filter and fluid replaced), but don't know for sure. Maybe low pressure to the clutches? Any ideas?

Max

could this be the dreaded b2 piston, although it does not usually affect reverse.