operators_manual

WARNING
Using an engine retarder can cause a
wheel lockup. The trailer is not loading
the tires enough to give the traction
you may need. When you are bobtail
or unloaded, you can have a serious
accident if your wheels lock suddenly
during braking. You could be killed or
injured. Don’t use your retarder when
you are driving bobtail or with an un-
loaded trailer.
WARNING
Do not rely on your automatic trans-
mission hydraulic retarder to stop your
vehicle. If your engine shuts down, the
vehicle’s retarder will cease to operate
which may lead to an accident involv-
ing death or personal injury. Always be
ready to suddenly apply the service
brakes.
Related concepts
Axle and Suspension
Differential Lock
The vehicle may be equipped with
switches to lock the either of the rear axle
differentials. 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 differentials 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.
Dual Range (Two-Speed) Rear Axle
Your vehicle may be equipped with a two-
speed or dual range axle (option). You can
select two rear axle ratios for operating
DRIVING - Axle and Suspension
156 Y53-6047-2HEN (03/18)
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