simple
it sends 1/3 of it's torque to the front wheels and 2/3rd to the rear via the gearing in the transfer box
the vc makes no difference to the torque split under normal driving conditions as it is locked all the time
only when the rear prop starts to turn faster than the front will yo get the torque going to the front prop via the vc and chain afterwards

if you were to remove the front prop the vc would burn out very quickly, in a matter on a mile or so, and then you would be left with no drive at all as all the torque would be being sent through the path of least risistance, ie the front prop, and seeing as it's not there, you won't get any drive going to the rear