Well if you talk to the designer of the trans he will tell you that it should last the life of the car. BUT in the real world with good service 200K-250K miles is a good figure.
Have replaced MANY transmissions under the warranty period 4year/50K miles.
TRY changing the fluid & filter first. IF the filter is plugged then you will have this type of problem.
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)