Hi, I recently banged my father's C220 against the garage door. Everything was repaired but now when i drive the
car, I think that there is a transmission problem. when I'm on 4th gear the car won't go above 60km/h. in fact the speed goes down so i have to shift back to 3rd and then 4th. the car takes a while to start running normally. Can anyone please help me understand what has gone wrong? thanks.

 

Sorry to hear of your troubles. The first thing I would do is see if there are any trouble codes lurking. This should be free at any MB dealer or some Auto Parts stores can help out here. (Auto Zone in my part of the world.) I'm refering to a read out from an OBDII scope.
Check to see if your transmission fluid is low.
Also, check out this link http://www.continentalimports.com/ser_ic20242.html
It's all about MB transmissions.

Good luck.