been there done that as far back as 1999 and was the very first person to do it so this is what you need to do

you need to find a diseasal mt75 box from a diseasal ford scorpio (not a granada scorpio, a ford scoprio, the one with the ugly face)
you then need to find a 2wd mt75 gearbox from any dohc sierra
then you need a gearbox from an xr4x4 2.9, no other box will do, and it was, at a time, cheaper to buy a complete car as you will also need the flywheel, pedal box etc from it

bolting it together in a bit