Peterbilt Medium Duty Truck Owner's Manual - Peterbilt Motors

STARTING AND OPERATING THE VEHICLE
stroke of the clutch pedal is about 10 inches. The first
part is the release stroke: the part that fully releases
the clutch. The last inch engages the clutch brake.
During hard-shifting with vehicle not moving
• To apply the clutch brake (while the vehicle is
stopped) fully depress the clutch pedal to the floorboard
to stop the gears. With the throttle at idle, select
first gear then release the clutch pedal to let the vehicle
start forward, until the clutch is fully engaged. See
the transmission manufacturer's manual that is
included with your vehicle for further details.
During Normal Driving
If you want to shift directly into any gear other than first or
reverse, depress the clutch pedal only far enough to
release the clutch. Pushing the clutch to the floor applies
the clutch brake and could cause gear hang-up.
OPERATING THE TRANSMISSION
CAUTION: Be careful not to apply the clutch
brake while the vehicle is moving. The purpose
of the clutch brake is to stop the transmission
so that you can shift into a starting
gear without grinding gears. Applying the
clutch brake when the vehicle is moving
causes a braking effect on the drivetrain
and shortens the service life of the clutch
brake.
Double Clutching
Whether you are upshifting or down shifting, it is best to
double clutch. Double clutching is easier on the transmission
and on the engine, helping your vehicle match engine
speed with driveline speed and achieving clash-free
shifts.
To double clutch:
1. Push the clutch pedal down to disengage the clutch.
2. Move the gear shift lever to Neutral.
3. Release the pedal to engage the clutch. This lets you
control the rpm of the mainshaft gears, allowing you to
match the rpm of the mainshaft gears to those of the
output shaft.
Medium Duty (R05/09) Y53-6027 – 101 –