vibrating or thumping noise when accellerating
 

I have an 89 300 SE and the transmission shifts very smoothly, but when you pull out from a dead stop, the car makes a noise like a vibration or thumping that only lasts for a few seconds and generally you do not hear it again. Occassionally, you can hear this same type noise when you hit a bump in the road. I believe the shocks have been replaced shortly before I purchased the car. Could it be the shocks or something loose? Or, could it be a beginning of a problem with the transmission? Also, does anyone know where I can get a service manual such as a Mercedes shop manual or a haynes/chiltons?

Scott

Sounds like a broken motor mount to me...

www.toadhallbook.com is where I got my Haynes manual for my W124...I don't remember the link though...do a web search.

Perhaps a rubber driveshaft 'flex disk'. There are 2 of these on the driveline. About $60 each for the part. They look like this:

http://img.eautopartscatalog.com/live/K102055631LEM.JPG

When 6 cylinder gas 126 car motor mounts collapse, the exhaust pipe hits the bolt in support connecting to the front suspension thrust mount brackets to each other. You probably need engine mounts. Don't forget to check the transmission mount, too. If you get under the car, you will see where the metal support has been hitting the exhaust.

Scott P.