Use lockout when approaching: ice, snow, mud, wet surfaces, or loose terrain.

Lockout Operation
1. Temporarily release the accelerator pedal. This interrupts the torque
applied to the inter-axle differential allowing easy engagement or disengagement
at any speed.

2. Flip the lockout selector valve to lock (engage) or unlock (disengage)
the lockout.

Remember:
• Engage lockout at any speed with accelerator released. Never
engage lockout when wheels are slipping.
• Use only under poor traction. Do not operate truck with lockout
“engaged” on dry pavement.

How it works;

Tandem axles will rotate at different speeds when cornering, driving over
uneven road surfaces or when equipped with different tire sizes.
The inter-axle differential is simply a mechanism that lets one axle rotate faster
or slower than the other. Under normal conditions it splits the torque evenly
between the 2 axles.
When extra traction is needed under adverse road conditions, you can lock out
the inter-axle differential. With the lockout engaged (LOCK position), the interaxle
differential acts as a solid shaft and does not compensate for differences
in axle speed, but directs the torque to the axle with the most traction.
With the lockout disengaged (UNLOCK position), the inter-axle differential
operates normally.

The Dana Drive Axle Wheel Differential Lock is an air-actuated clutch which
positively locks the differential gearing in the rear axle. When this clutch is
engaged, power flows to the tires without any differential action, giving each
wheel all the torque the road conditions will permit.

The Wheel Differential Lock is engaged by a cab-mounted valve, causing the
clutch to move in or out of engagement. This motion also trips an electrical
switch used to activate a light in the cab or sound an audible device, indicating
that the Wheel Differential Lock is engaged.

WARNING: Do NOT use your Wheel Differential Lock when traveling
downhill

WARNING: Do NOT use your Wheel Differential Lock at speeds over
25 mph

Engage
1. Flip the control lever to the “Lock” position, either while the vehicle
is stationary, or while moving at a steady speed under 25 miles per
hour without the wheels slipping (spin out).
2. Let up momentarily on the accelerator pedal to relieve torque on the
gearing and fully engage the clutch.
3. When the differential lock is engaged, the indicator light will be on, or
an audible signal will sound.
4. When the differential lock is engaged, the vehicle will understeer,
requiring a longer turning radius for a given turn.

Disengage
1. To disengage the Wheel Differential Lock, flip the control lever to
“Unlock”.
2. Let up momentarily on the accelerator pedal to relieve torque and
allow the clutch to disengage.
3. When the differential lock is disengaged, the indicator light and/or
audible signal will go out.
WARNING: Engage Wheel Differential Lock ONLY when vehicle is
stationary, or moving without wheel slippage.

Important To Remember
When engaged, the Wheel Differential Lock will cause the vehicle to understeer,
meaning that the vehicle will not turn as quickly, and more steering
effort will be required.
Use your Wheel Differential Lock only at speeds less than 25 miles per
hour; at higher speeds, the understeer handling characteristics could be
dangerous.
The differential lock should be engaged only when the vehicle is stationary,
or moving without wheel slippage (spin out).
This system should only be used when poor traction is encountered; it
should be disengaged under normal traction conditions.