With the 722.3 OLD GEARBOX The Engine controller needet to know the what gear the gearbox was in, it was told by resistors, we solved it this way.

The new Gearbox Controller read gearLever position from new Gear Lever.

And depending on if it is in P/N or in R/D/4/3/2/1 Engine Controller gets 2 differen resistor values.

First mount an Gear Lever from W202 that fits the plug i have on my controller. the PRND4321 tybe.

Then an output to 1 relay, that is active when in  P and N and not active when in RD4321

and then i would only tell the engine controller if in P / D that should be fine.

This setting should be done.

“Boost Control” -> “General Boost” -> “USE PWM - AUX-2”

If set to “2” then the AUX-2 pulls the output to ground when in P or N