
To return to a previously set speed
Instrument panel-mounted
controls:Press RESUME -. For
RESUME - to operate, the vehicle
speed must be above 30 mph (48
km/h) or engine speed must be
above 1,000 RPM.
Steering wheel-mounted
controls:Press RES. For RES to
operate, the vehicle speed must be
above 30 mph (48 km/h).
SET RESUME
RES
SET
ACCEL
COAST
Driver controls
63

HYDRAULIC BRAKES (IF EQUIPPED)
Your service brakes are self-adjusting. Refer to theGeneral
Maintenance Informationfor scheduled maintenance.
Occasional brake noise is normal and often does not indicate a
performance concern with the vehicle’s brake system. In normal
operation, automotive brake systems may emit occasional or intermittent
squeal or groan noises when the brakes are applied. Such noises are
usually heard during the first few brake applications in the morning;
however, they may be heard at any time while braking and can be
aggravated by environmental conditions such as cold, heat, moisture,
road dust, salt or mud. If a“metal-to-metal,”“continuous grinding”or
“continuous squeal”sound is present while braking, the brake linings
may be worn-out and should be inspected by a qualified service
technician.
If you are driving down a long or steep hill, shift to a lower gear.
Do not apply your brakes continuously, as they may overheat
and become less effective.
Note:Normally, choose the same gear to descend the hill that you would
use to ascend the hill.
IF BRAKES DO NOT GRIP WELL
•If you have been driving through deep water, gently apply the brakes
several times while the vehicle is moving slowly.
•Let the brakes cool if you have been using them excessively, as in
mountain driving or after several fast, high speed stops.
•Check brake adjustment.
•Check brake linings for excessive wear.
Hydraulic brake booster system (Hydromax)
The Hydromax systems receive fluid pressure from the power steering
pump to provide power assist during braking.
The Hydromax booster receives backup pressure from the reserve
system electric pump whenever the fluid in the power steering system is
not flowing. When the engine is OFF, the pump will turn on if the brake
pedal is applied, or if the ignition is turned to the ON position.
The sound of the pump operating may be heard by the driver, but this is
a normal characteristic of the system.
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93

Releasing the parking brake
Note:Read and understand the following steps and perform them
whenever you prepare to drive the vehicle.
Note:The parking brake will not disengage unless sufficient system air
pressure is available.
For vehicles with automatic transmissions - dash-mounted push
button (Allison MD) and steering column-mounted (Allison 2000
and 2400) gear selection:
1. With the engine running, depress and hold the service brake pedal.
2. Wait until system air pressure is above 100 psi.
3. Select the appropriate drive gear.
4. Push the yellow, dash-mounted parking brake knob.
For vehicles with manual transmissions - (TTC 7–speed,
Eaton/Fuller 5–speed, 6–speed and 10–speed):
1. With the engine running, depress and hold the service brake pedal.
2. Wait until system air pressure is above 100 psi.
3. Depress and hold the clutch pedal.
4. Select the appropriate drive gear.
5. Push the yellow, dash-mounted parking brake knob.
Hold the brake pedal down while moving the gearshift lever from
position to position. If the brake pedal is not held down, the
vehicle may move unexpectedly resulting in property damage, personal
injury or death.
Parking brake light illumination due to low air pressure
If at any time during vehicle operation air pressure is too low, the
parking brake may apply and the parking brake light will turn on.
If the parking brake is applied due to low air pressure, immediate service
is required to the parking brake system.
Parking brake warning system
If the park brake light blinks and a chime sounds when pulling the yellow
control knob out, this indicates the parking brake is not functioning
properly; seek service for the parking brake immediately.
The light will blink and the chime will sound until the yellow control
knob is pushed in or approximately eight minutes have passed. If the
Driving
97

Actuation of trailer park (emergency) or tractor bobtail position
To actuate the trailer brakes only, pull out the trailer air supply knob (1).
The trailer brakes are now applied whether emergency or spring brakes
are used on the trailer.
This mode is also used when the tractor or truck with trailer is used
during bobtail operation.
ANTI-LOCK BRAKE SYSTEM (ABS)
Four-wheel anti-lock brake system (ABS)
A noise from the hydraulic pump motor and pulsation in the pedal may
be observed during ABS braking events. Pedal pulsation coupled with
noise while braking under panic conditions or on loose gravel, bumps,
wet or snowy roads is normal and indicates proper functioning of the
vehicle’s ABS. If the vehicle has continuous vibration or shudder in the
steering wheel while braking, the vehicle should be inspected by a
qualified service technician.
The ABS operates by detecting the
onset of wheel lockup during brake
applications and compensating for
this tendency. The wheels are
prevented from locking even when
the brakes are firmly applied. The
accompanying illustration depicts
the advantage of an ABS equipped
vehicle (on bottom) to a non-ABS
equipped vehicle (on top) during hard braking with loss of front braking
traction.
1
2
Driving
113

ABS warning lamp
The
ABSwarning lamp in the instrument cluster momentarily illuminates
when the ignition is turned on and the engine is off. If the light does not
illuminate momentarily at start up, remains on after the vehicle reaches
5–10 mph (10–15 km/h), or continues to flash, the ABS needs to be
serviced.
With the ABS light on, the anti-lock brake system is disabled and normal
braking is still effective unless the brake warning light also remains
illuminated. (If your parking brake warning lamp illuminates, have your
vehicle serviced immediately).
Using ABS
•In an emergency or when maximum efficiency from the ABS is
required, apply continuous full force on the brake. The ABS will be
activated immediately, thus allowing you to retain full steering control
of your vehicle and, providing there is sufficient space, will enable you
to avoid obstacles and bring the vehicle to a controlled stop.
•The ABS does not decrease the time necessary to apply the brakes or
always reduce stopping distance. Always leave enough room between
your vehicle and the vehicle in front of you to stop.
•We recommend that you familiarize yourself with this braking
technique. However, avoid taking any unnecessary risks.
TRACTION CONTROL(IF EQUIPPED)
Your vehicle may be equipped with a Traction Controlsystem. This
system helps you maintain the stability and steerability of your vehicle,
especially on slippery road surfaces such as snow- or ice-covered roads
and gravel roads, by reducing engine power and/or selectively applying
the rear brakes. The system will allow your vehicle to make better use of
available traction in these conditions.
Note:The traction control system will not apply the brakes when the
vehicle speed is above 25 mph (40 km/h).
During Traction Controloperation,
the traction control light in the
instrument cluster will flash and the
engine will not“rev-up”when you
push further on the accelerator. This
is normal system behavior and should be no reason for concern. If the
traction control light does not flash or stays illuminated, the system is
not functioning.
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114

When operating a loaded vehicle, the driver must keep all
adjustable axles on the ground at all times, supporting their
share of the vehicle’s load. Failure to do so can overload other axles,
tires, wheels, springs, steering components, brakes and frames,
resulting in early component failure, loss of vehicle control, possible
property damage and personal injury.
FIFTH WHEEL OPERATION
Failure to follow the fifth wheel manufacturer’s instructions for
hooking and unhooking as well as sliding the fifth wheel could
result in an accident, personal injury or death.
When the tractor and trailer are parked unattended, the trailer
brake hand control should never be used to apply the brake,
since air may leak from the system, allowing vehicle movement,
resulting in possible property damage, personal injury or death.
Hook-up
1. Fifth wheel jaws must be fully opened.
2. Tilt the fifth wheel back to prevent body damage when the tractor is
backed under a trailer.
3. Block the trailer wheels and be sure the trailer spring brakes are
adjusted and applied. Never chase a trailer.
4. Make sure the brake hoses and light cords are clear of the fifth wheel.
5. Back the tractor squarely under the trailer, engaging the fifth wheel
jaws on the kingpin. Always back-up slowly, making sure the trailer is
neither too high nor too low. Avoid backing under the trailer from an
angle.
6. Connect the service and emergency brake hoses and trailer light
connector. Refer toTractor-trailer connectionin this chapter, adhering
to the warning and using the three-point stance while connecting and
disconnecting the trailer.
7. Inspect the jaws of the fifth wheel to be sure they have fully closed on
the trailer kingpin and the trailer plate is resting securely on the fifth
wheel.
8. Be sure the coupler release lever is in the locked position.
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117

Axle conversions
It is not recommended, or approved, for axle conversions to be
performed. However, it is understood that, on occasion, aftermarket
add-on axles are installed by others on the truck chassis which allow
operator control for weight transfer from other axles (i.e., air lift axles).
When operating a loaded vehicle, the driver must keep all
adjustable axles on the ground at all times, supporting their
share of the vehicle’s load. Failure to do so can overload other axles,
tires, wheels, springs, steering components, brakes and frames,
resulting in early component failure, loss of vehicle control, possible
property damage and personal injury.
TWO-SPEED REAR AXLE (IF EQUIPPED)
A two-speed rear axle allows the driver to select a LO range for greater
pulling power and a HI range for greater road speed and fuel economy.
These ranges can also be used to provide additional steps between
transmission shifts when driving on steep grades and/or fuel economy
may be factors.
Note:Do not shift between ranges when the speed control is on.
Never shift a two-speed axle when descending a steep grade as
this may cause loss of vehicle control and result in personal
injury.
Axle shifting
Manual transmissions:
•To downshift,select the next lower gear, release and depress the
accelerator pedal rapidly, or while holding the accelerator pedal down,
release and engage the clutch rapidly.Note:The clutch method is
recommended when driving at slower speeds.
•To upshift,keep the accelerator pedal down, select the next higher
gear, release the accelerator and pause until the axle upshifts.Note:
De-clutch for smoother axle upshifts when driving at slower speeds.
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132

HAZARD FLASHER
The hazard flasher control is located
on the steering column, just behind
the steering wheel. The hazard
flashers will operate when the
ignition is off.
Push in the flasher control and all
front and rear direction signals will
flash. Press the flasher control again
to turn them off. Use it when your
vehicle is disabled and is creating a
safety hazard for other motorists.
Note:With extended use, the flasher may run down your battery.
FUSING
If electrical components in the vehicle are not working, a fuse may have
blown. Blown fuses are identified by a broken wire within the fuse.
Check the appropriate fuses before replacing any electrical components.
Note:Always replace a fuse with one that has the specified amperage
rating. Using a fuse with a higher amperage rating can cause severe wire
damage and could start a fire.
Roadside emergencies
140