One problem related to transmission failure has been reported for the 2003 Mercedes Benz Clk Class. The most recently reported issues are listed below.
Transmission failure. Rusted and corroded trans at 24,000 miles caused by faulty mercedes valeo radiator. Mercedes own star bulletin tells dealers about this issue but my dealer decided not to check it out and now mercedes and dealer are refusing to help when this is a known problem on many of their models and should be a recall.