Having always had standard tranmission cars, I have a question concerning the automatic C220 my mother purchased new. The car is a 95 with only 19,000 city miles on it. I did the search and still have some questions. Does this car have a dipstick? There is a cap with a lock on it which says to maintain by M-B dealer only. Can I remove this cap and check the A/T? Should I change the fluid and use Mobil Synthetic. It is not the smoothest shifting car especially when it is cold.