For the 550i, both LCI and pre-LCI show the transmission to be GA6HP26Z. The one difference I can find part number-wise is the mechatronics unit is P/N 2434751229 for pre-LCI and 24007571248 for after.

The pre-LCI have a bowden cable that connects directly to the transmission, where the LCI went to an electronic shifter with 6 wires that do this: (according to WDS)

PIN 1 Power PIN 40 red/gold Junction box trunk connector X11012
PIN 2 White wire to transmission (round plug) PIN 8
PIN 3 PT-CAN Low - PIN 32 blue/red (connector X13581 - lower right corner plug)
PIN 4 PT-CAN High - PIN 34 red
PIN 5 CAS wake-up signal is pin 15 red/green
PIN 6 Ground to chassis

We could easily buy a used 08+ transmission for his car, but we were wondering if the mechatronics unit would really be all that is needed, and possibly and new transmission module.

Does anyone have any experience with this?

Thanks!

 

keep as posted..