"All wheel Drive" or "Full Time 4WD" is actually a marketing term designed only to sell to consumers.
AWD is diffs times 3. Front, Center and Rear. Lift one up and if the center is open or unlocked, it's game over. All the power will go to it and since it has no traction forward progress will be halted. So hardly "All" wheel drive.
So if the Christini was AWD a simple wheelie would stop it.
The Christini is PTO with the assistance of a sprag clutch.
Like GM or Chrysler's "Select Track" or similar. Only, that system has independent wheel speed sensors that tell the transfer case when to lock up...
They steer it as AWD to the AWD customer as well.
Again, AWD like a Land Rover Defender, Landcruiser FJ80, Merc G-Wagon, Audi Quatro, Lamborghini (V drive) and Porsche C4
are diffs x 3.