mercedes-benz e430 clunk from park to reverse
Possibly a universal joint going bad. The differential could have bearing wear as well. The transmission mount may need replacement.
It's kind of hard to diagnose your problem with so little info to go on.....so based on the year of the car, the first thing I would check is the flex disc on the drive shaft...and there may be two, one in the front by the trans output and the other should be right in front of the rear differential. These flex discs are rubber and absorb drive line shock to smooth out the power delivery to the rear differential. Search Youtube for a video on these items as if they fail while you are driving, it can be very damaging to you car.
Looking for a Used E-Class in your area?
CarGurus has 19,789 nationwide E-Class listings starting at $1,200.
Search Mercedes-Benz E-Class Questions
Mercedes-Benz E-Class Experts