---------------From the workshop manual----------------

VARI-LOK DIFFERENTIAL
=====================

DESCRIPTION
+++++++++++
Vari-lok differentials are a speed-sensing torque transfer
differential.

Unlike typical differential systems, torque transfer is
proportional to wheel speed difference rather than torque
difference.


OPERATION
+++++++++
As a wheel begins to lose traction, the speed differential is
transmitted from one side of the differential to the other
through the side gears. The motion of one side gear relative to
the other turns the inner rotor of the pump. Since the outer
rotor of the pump is grounded to the differential case, the inner
and outer rotors are now moving relative to each other and
therefore creates pressure in the pump.

The tuning of the front and rear axle orifices and valves inside
the gerotor pump is unique and each system includes a
torque-limiting pressure relief valve to protect the clutch pack,
which also facilitates vehicle control under extreme side-to-side
traction varia-tions. The resulting pressure is applied to the
clutch pack and the transfer of torque is completed.

---------------Workshop manual quote ends----------------