User Manual

Engine Brake Level (3 position)
Switch Position Amount of Engine
Braking
Top High – 100%
Middle Medium – 66%
Bottom Low – 33%
See your Engine Operation and
Maintenance Manual or Engine Brake
Operation Manual for further details on
using engine retarders.
Engine Brake Indicator
provides acceleration. In these cases, the
engine brake indicator will turn white while
acceleration is being applied.
Axle and Suspension
Differential Lock
The vehicle may be equipped with
switches to lock the either of the rear axle
dif
ferentials. Depending on how the vehicle
is specified, a combination of individual
switches may be available that can lock the
interaxle driveline and/or any combination
of the forward rear or rear-rear driving
axles. The interaxle differential switch
allows each axle to turn independently. In
certain situations, engaging the interaxle
differential lock relieves stress on the rear
axles and reduces tire wear. Engaging this
switch will also provide better traction in
slippery or loose gravel conditions.
In the LOCK position, continuous operation
on paved, dry surfaces, put stress on the
axles, and can possibly damage the
internal gears. The switch has a guard to
prevent accidental operation of the switch.
Locking the dif
ferentials is typically used
during ice or snow conditions and without
tire chains, unpaved roads that have loose
sand, mud or uneven surfaces. Look
ahead and predict when the differential
needs to be locked. Stop the vehicle and
lock the differentials before approaching.
While using the differential in the locked
position, do not exceed 25 mph (40 km/h).
When disengaging the differential lock,
reduce the throttle to prevent drivetrain
damage.
WARNING
DO NOT put the differential lock in the
LOCK position while the wheels are
spinning freely (slipping), you could
lose control of the vehicle or cause
axle damage. Switch to LOCK only
when the wheels are not spinning.
Failure to comply may result in death,
personal injury, equipment or property
damage.
DRIVING - Axle and Suspension
When engine braking is active, this (green)
indicator will appear. Vehicles with an
engine braking level switch show the
degree of engine braking applied using
dots below the indicator. Active engine
braking can be overridden when the
operator or a truck feature (like the
Adaptive Cruise Control (ACC) option)
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