If you use free wheel hubs,
you can stop the whole impulse-cord
(impulse-shaft, differencial)
on vehicles with switchable all-wheel-impulse
on the 2WD-working.
Profit:
fewer wear on the
impulse-cord and the front-tires,
easier driving and fewer
fuel-consumption
because smaller roll-resistance.
Further the manual
free-wheel-hubs have the profit, that you know,
if they are switched or not.
Important:
please asways control both sides and
switch opportune.