A common misconception suggests that a 4x4 and traction go hand in
hand… you can't have one without the other. The truth, however, is
that most 4x4 vehicles send power to the wheels with the least amount
of traction once difficult terrain is encountered. The problem is simple -
when one (or more) of your vehicle's wheels loses traction, your highway
minded factory differential directs all of your vehicle's power to those
spinning wheels. On road, the standard "open" differential allows each
of your wheels to turn independently thus eliminating any binding during
turns. Off road, this becomes a major burden as engine power will take
the path of least resistance, which occurs at the wheels with little or no
traction.

Newer vehicles with limited slip differentials (LSDs), positraction etc may
offer some improvement over standard differentials, but more often you'll
find the slipping is not "limited" enough to maintain forward progress.
Automatic locking differentials also have their disadvantages. Aside from
being noisy, automatic locking differentials often upset the on highway
and off road driving characteristics of your 4x4. During normal driving
conditions, vehicle responsiveness becomes less predictable, and when
highway surfaces become wet or icy, the driver must use extreme
caution just to keep the truck in control.

Note: Air compressor kit needed to make lockers work, these are sold seprately.