Y61 from 2001 on came with a 3.0 Di [ZD 30] engine etc..
Contact HERRIE OP SAFARIE aka Kobus Pienaar and get the CD MANUAL of the Patrol .. it will give you the diff ratios etc ..
CHARLES DUCKETT did a 4,8 conversion on his GQ 4,2 petrol Patrol .. and almost everything fitted perfect [it is a design feature of the patrol that the platform stays as is .. just the mechanicals updates ..
Computer aka ECU ?? Absolutely -- MUST have one -- else thet engine will be dead forever [less you fit it with truly OLD SCHOOL diesel pump of the 1980's 2,5 Datsun Tracker 2,5 diesel engine [NOW I'm guessing]