My guess is that your problem is in the drive shaft area.
These cars have a driveline that has flexible rubber discs at both ends (called flex discs) instead of a traditional U-joint, and a center U-joint with a support bearing.
Further, the front flex disc usually wears out, and is probably shot if it hasn't been replaced already, too.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".