My wife has a 1998 #320 all wheel drive model with about 80,000 miles and it has a vibration I am trying to track down. It starts around 55 is worst around 63 and get better at higher speeds. The vibration is not in the steering wheel but rather you tend to feel it thru the seat and the floor. I am not familiar with the flex disk in the mercedes but to me what she has a similar vibration as a bad u joint but of course I do not have the tell tale clunk when shifting from reverse to drive you get with a u joint. Is there a way to check for a bad flex joint? I took a look underneath and between the tranny mount and everything else I cannot even get a hand the flex disk.

 

I kinda the same issue except it is the sterring wheel at about them speeds. In my case it is the Break Rotors. I would take it to a local shop and have them take a look at it. Do not go to a dealer.

 

Thanks,

I will check that out

 

I have a 1999 430E with the same problem. bought car with 50,000 KLM and took it to the dealer. he told me that they had tried to address this with another customer and had failed. It is was worst at 80 to 100 KLM (50 to 60 mph) I had the universal joint replaced driveshaft ballanced.
It was a little better but not gone. I fiddled a long time with position swapped flex couplings front to back etc. with no change.
Placed a 40 thousand spacer between the frame and the support bearing mount which made the problem tolerable.
I have now added 120,00 klm with no change in the vibration. This vibration is also more noticeable in colder temperatures.
I have read somewhere that this is caused by the support bearing housing although I did not see anything wrong with mine.
Brum Brum Brum resonant thruout the chasis.