Probably been asked a thousand times. but bear with it again. I have a 1998 E300 Turbodiesel.........was told by dealer that factory fill of transmission fluid and the filter was good for the life of the car. And as you know the dipstick is sealed.
So, what is the real story by the master techs here? Leave it alone forever, or change the fluid and filter at what mileage. I now have 60 K trouble free miles.
2001 C320 Sport
2000 SAAB 9-5
1972 Porsche 911 Targa