As I have posted many times, these transmissions as well as all others will fail. ONE of the problems is the MB recommends not changing the fluid & filter. However as most people realize fluid will fail no mater who makes it. SHELL makes this fluid for MB!!
However in your case I believe that the valve body & trans computer has led to early failure.
THE cost $$$ of a retrans is very high, at least $3,500.
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)