TOD and no rear driveshaft....

[Ebenezr]

I'm reasonably sure, after a few conversations on the stoop in Moab, that you would also need the computer & frt axle from the donor Trooper.
The Troop frt axle is vacuum controlled, which would also need to be addressed...http://www.4x4wire.com/isuzu/tech/fwd_lockout/?

I don't understand the vacuum actuator mechanism but I did look at the Trooper info in the manual and there is a 4 bolt flange coming out of the front pumpkin to connect to a more robust front drive shaft. If TOD is present on the Trooper then it has a round 6 bolt flange to connect to the limp wristed Front TOD shaft. At least the length of Trooper and VX front shafts are identical 22.7 inches. So I'm with Chris - the next move may be a 4 hi transfer case with no TOD wiring!!!

[Ldub]

I don't understand the vacuum actuator mechanism

I believe it's for the shift on the fly function.