no ide if this would relate but I had a simular issue with my 99 e320. after months of troubleshooting, and even going so far as replacing the transmission (car started to drop out of overdrive etc) it turned out to be the computer in the auto shifter had crap spilled all over it. someones nice sugary hot beverage, couple cokes who knows. swap at new shifter in from a wreak and never another issue