Glad you found the problem.

For anyone who follows this, the range recognition switch is a replaceable part within the shifter.

You have to remove the shifter and disassemble it to remove the switch cartridge.

Before buying a new one try popping the switch casing open and clean the circuit board with alcohol. When you move the shift handle, you are sliding contact pads across a circuit board. Spilled liquids down the shifter wreak havoc with this system.

The transmission mechanically detects the P, R, N, and D positions by motion of the shaft. The 4-3-2-1 and the S/W switch are only digital inputs to the TCM. Once the handle is pulled from D to 4 the handle is decoupled from the transmission shaft (which stays in D) and the handle continues to move the slider down the circuit board.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech