If you can't physically move the shifter into reverse at times???.. the problem IS in the valve body.
ALL MB auto boxes have a reverse lock-out that keeps you from engaging reverse gear when you are going 3MPH of faster.
A piston in the rear section of the valve body pops out from governor pressure to stop the shift lever from moving.
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
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42 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)