I have 90K on 97 S500 don't know the history of the car since it was a used purchase. The car has no hard shifting problem, runs smooth, transmission just smells at 100mph when forced to do it. Have not changed fluids since 2004 when first bought it. Only put 6K a year, driving weekends mostly. E420 is the daily commuter. I just hope the smell is from the fluids overheating and not anything mechanical. I never drive over 100mph, but in this car or any V8 Mercedes, it is very easy to make such mistake.