OPERATOR'S MANUAL

CONTROLS AND DISPLAY DASH- AND DOOR-MOUNTED FEATURES
Medium Duty
(R05/09) Y53-6027 – 61 –
• If you have the two-mode system, you can select
HIGH or LOW.
• If you have the three-mode system, you can select
low, medium, or high retarding.
WARNING! Do not use the Jacob’s brake as
the primary means of slowing or stopping the
vehicle. The Jacob’s brake is designed to be
used in conjunction with the service brakes.
Failure to do this may cause death or personal
injury.
Interaxle Differential Lock Switch
The interaxle differential allows differential action between
the forward rear and the rear rear driving axles. The inter-
axle differential lock switch allows the operator to LOCK or
UNLOCK the differential. The guard over this switch pre-
vents you from accidentally activating the lock.
WARNING! Placing the differential lock in the
“LOCK” position while your wheels are spin-
ning could cause loss of control or axle dam-
age. there could be an accident involving
death or personal injury. Switch to “LOCK”
only when your wheels are not spinning.
See “Interaxle Differential” on page 95 for more informa-
tion on using your interaxle differential.
SHIFT AT ANY SPEED EXCEPT
IF A WHEEL IS SPINNING