My 1994 E420 has 131,000 miles, and is on the original transmission. Whenever I shift into reverse, there is a 2 second delay before reverse engages. Once it is in gear, reverse behaves normally. There is no delay whatsoever in Drive. Is this indicative of a problem? Since I have owned the car, I have changed the transmission fluid and filter every 30,000 miles. I intend to drive the car for a very long time, and just want to do everything I can to make it last. Ordinarily, with transmission problems, I have always been told to drive it until it drives no more, but just wanted to be sure that adage holds true in this situation. Thanks!