Dual Range (Two-Speed) Rear Axle - Peterbilt 579 Operator's Manual

AXLE
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 under heavy loads or rough
terrain as well as for over the road
hauling.
4
The Low Range provides maximum
torque for hauling heavy loads or
traveling over rough terrain. The High
Range is a faster ratio for highway
speeds and general over the road
conditions. A switch on the accessory
switch panel controls the Dual Range
Rear Axle. You will notice that the
switch has a guard to protect you from
activating it accidentally. Always park
your vehicle with the range selector in
LOW.
4-40
Dual Range Axle Operation
Important tips on operating a Dual
Range Axle with Interaxle Differential:
•
Shift the axle with the inter-axle
differential in the unlocked position
only.
•
When you are driving with poor
traction, lock the differential. When
you have the differential locked,
drive with the axle in LOW range
only.
•
When you are driving on a surface
with good traction, keep the
interaxle differential unlocked. You
can drive with the axle in the LOW
or HIGH range.
•
Always UNLOCK the inter-axle
differential before shifting the axle
speed range.
Y53-6047–2C
CAUTION
If you shift the axle range with the in-
ter-axle differential in LOCK, you could
seriously damage the axles. Never
shift the axle range with the differen-
tial locked.
(04/13)