Paccar PX-9 Operator's Manual - page 50
OPERATING INSTRUCTIONS
WARNING!
DO NOT use an engine brake
when driving bobtail or with an un-
loaded trailer. There may not be
enough weight on the rear axle to
provide traction. This could cause
a loss of control and jackknife re-
sulting in an injury accident. Make
sure the engine brake is switched
“OFF” when bobtailing or with an
unloaded trailer. Failure to com-
ply may result in death, personal
injury, equipment or property dam-
age.
To reduce vehicle speed, put the
engine brake “ON/OFF” switch in the
“ON” position. Remove your foot from
the accelerator pedal and clutch pedal.
The engine brakes will immediately
begin to operate, slowing the vehicle.
For operation on dry and relatively flat
surfaces, when greater retarding power
is not required, put the two-position
selector switch in the “LOW” position.
For operation on dry pavement when
maximum retarding power is required,
put the two-position selector switch in
the “HI” position.
Tips for Operation on Grades
with Dry Pavement
WARNING!
The engine brake is not intended
as the primary brake for the vehi-
cle, nor is it an emergency brake.
The service brakes must be used
in an emergency. Relying solely on
the engine brake to stop the vehi-
cle in an emergency could cause
an accident and lead to personal
injury. The engine brake only helps
the service brakes by using pres-
sure to slow the drive train. You
must use the service brakes for
quick or emergency stops. Failure
to comply may result in death, per-
sonal injury, equipment or property
damage.
“Control speed” is the speed at which
the forces pushing a vehicle down a
grade are equal to the forces holding
it back.
4-14
Y53-1185-1B1
(12/2014)
4