For vehicles with selectable four-wheel drive
you can be using
free-wheel hub
to shut down the entire drive train (drive shafts, differential)
in
2WD mode.
Advantage:
Less
wear on the impulse-cord and the front-tires,
easier driving and less
fuel-consumption
because of smaller roll-resistance
The manual
free-wheel-hubs have the additional advantage, that it lets you
know,
whether they are switched on or not.
Important:
Always control both sides and switch on in time.