I have a 1988 RR Classic with 200Tdi motor and 5 speed LT77s manual box with Borg Warner transfer box. The vehicle was originally fitted with the VM motor but the Tdi was retrofitted by the previous owner. I am thinking of fitting an auto box to replace the manual mainly as the vehicle is used for long journeys (400-600km) and the ease of an auto, coupled to the possibility of installing cruise control, are attractive. I have recently found a possible donor vehicle - a 1996 300Tdi Disco with 4 -speed box

Has anyone done this conversion before? Any pitfalls/problems? My concerns are mainly:
electrical circuitry - are there circuits required in the auto vehicle that are not present in the manual?
transfer box - presumably I would need to convert to the transfer box on the Disco