I have a 1998 SLK230 R170 bone stock.
Recently, I have had a 'thumping' sound under the car in the center, usually in second gear, upon accelerating. This just started. I did a search and came up with flex joint. I got under the car, the flex joint appears to be fine. However, on the other end of the drive shaft, just in front of the u-joint, there is a bearing that is bolted to the body, that the drive shaft enters. The technical name is 'Driveshaft support bearing'. It appears that the rubber that supports the bearing is badly deteriorated, and I can detect some play in the shaft. I have ordered the assembly from Autohaus. My question would be:
Is there a DIY for this?
If not, has someone done this, and if so, are there any 'gotchas' I need to be aware of?
I do see that I will have to drop the exhaust system to get to it, anyone know the part numbers for the nuts and bolts and gaskets that hold the exhaust together? I noted that the rear trianglular joint has badly rusted nuts and bolts, and in front there is a u-bolt also badly rusted.

Any help is appreciated. Thanks for reading.

 

Check also the engine mountings...

 

I have also a clonking noise under the car, but not so much on acceleration, but even when the car is rolling with very slow speed. I don't thing this comes from the diff, but who knows.

When I put the car in P and push it back and forth it makes a clunking noise as well.

 

In both cases this has to be the engine mounts...