One problem related to transmission slip out of gear has been reported for the 2006 Mercedes Benz C230. The most recently reported issues are listed below.
Vehicle would not shift out of 3 gear when driving 25 miles per hour. Rpm's went to 4,000 and I had to stop vehicle and restart. Ridiculous because no problems were "found" with vehicle but something is obviously wrong. I will never buy another Mercedes Benz what a lemon.