Peterbilt Medium Duty Truck Owner's Manual - Peterbilt Motors

CONTROLS AND DISPLAY
DASH- AND DOOR-MOUNTED FEATURES
• 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 interaxle
differential lock switch allows the operator to LOCK or
UNLOCK the differential. The guard over this switch prevents
you from accidentally activating the lock.
SHIFT AT ANY SPEED EXCEPT
IF A WHEEL IS SPINNING
WARNING! Placing the differential lock in the
“LOCK” position while your wheels are spinning
could cause loss of control or axle damage.
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 information
on using your interaxle differential.
Medium Duty (R05/09) Y53-6027 – 61 –