
Your Driving, the Road, and Your Vehicle..........4-2
Defensive Driving...........................................4-2
Drunken Driving.............................................4-3
Control of a Vehicle........................................4-6
Braking.........................................................4-6
Hydraulic Brake Systems.................................4-7
Anti-Lock Brake System (ABS).........................4-8
Braking in Emergencies...................................4-9
Trailer Brake Hand Control Valve....................4-10
Rear Axle Differential Lock Control..................4-11
Traction Control System (TCS).......................4-12
Steering......................................................4-13
Off-Road Recovery.......................................4-15
Passing.......................................................4-16
Loss of Control.............................................4-17
Driving at Night............................................4-18Driving in Rain and on Wet Roads..................4-20
City Driving..................................................4-23
Freeway Driving...........................................4-24
Highway Hypnosis........................................4-25
Hill and Mountain Roads................................4-26
Winter Driving..............................................4-27
If Your Vehicle is Stuck in Sand, Mud, Ice,
or Snow...................................................4-32
Rocking Your Vehicle to Get It Out.................4-32
Tow Hooks..................................................4-33
Loading Your Vehicle....................................4-34
Adding a Snow Plow or Similar Equipment.......4-36
Towing..........................................................4-37
Towing Your Vehicle.....................................4-37
Trailer Connections.......................................4-39
Section 4 Driving Your Vehicle
4-1

If Your Vehicle is Stuck in Sand,
Mud, Ice, or Snow
In order to free your vehicle when it is stuck, you will
need to spin the wheels, but you do not want to
spin your wheels too fast. The method known as rocking
can help you get out when you are stuck, but you
must use caution.
{CAUTION:
If you let your tires spin at high speed, they
can explode, and you or others could be
injured. And, the transmission or other parts of
the vehicle can overheat. That could cause an
engine compartment re or other damage.
When you are stuck, spin the wheels as little
as possible. Do not spin the wheels above
35 mph (55 km/h) as shown on the
speedometer.
Notice:Spinning your wheels can destroy parts of
your vehicle as well as the tires. If you spin the
wheels too fast while shifting your transmission
back and forth, you can destroy your transmission.
Rocking Your Vehicle to Get It Out
First, turn the steering wheel left and right. That will
clear the area around the front wheels. If you have a
four-wheel-drive vehicle, shift into 4HI. SeeFour-Wheel
Drive on page 2-35. If your vehicle has traction
control, you should turn the traction control system off.
SeeTraction Control System (TCS) on page 4-12.
Then shift back and forth between REVERSE (R) and a
forward gear, or with a manual transmission, between
FIRST (1) or SECOND (2) and REVERSE (R), spinning
the wheels as little as possible. Release the accelerator
pedal while you shift, and press lightly on the
accelerator pedal when the transmission is in gear. By
slowly spinning your wheels in the forward and
reverse directions, you will cause a rocking motion that
may free your vehicle. If that does not get you out
after a few tries, you may need to be towed out. If you
do need to be towed out, seeTowing Your Vehicle
on page 4-37.
4-32

Towing
Towing Your Vehicle
Consult your dealer or a professional towing service if
you need to have your disabled vehicle towed. See
Roadside Assistance Program on page 7-5.
Releasing Air-Operated Parking Brakes
If your vehicle has air brakes, you could have a
special towing problem. If your vehicle has to be towed
because of a complete loss of air pressure from
both systems, the parking brakes will have automatically
engaged. The tow operator can release the brakes
manually by using the following steps. Then your vehicle
can be towed with all wheels or only the rear wheels
on the ground.
1. Block the wheels of the vehicle.2. Remove the release stud and nut from the side of
the brake chamber. Some chambers have studs
which are visible at all times.
4-37

Trailer Connections
Heavy-Duty Trailer Wiring Package
Your vehicle may be equipped with an eight-wire trailer
towing harness. This harness, with a seven-pin
universal heavy-duty trailer connector, is attached to a
bracket on the platform hitch.
The Center High-Mounted Stoplamp (CHMSL) wire is
tied next to the trailer wiring harness for use with a
trailer.
The eight-wire harness contains the following trailer
circuits:
•Yellow: Left Stop/Turn Signal
•Dark Green: Right Stop/Turn Signal
•Brown: Taillamps
•White: Ground
•Light Green: Back-up Lamps
•Light Blue: CHMSL
•Red: Battery Feed
•Dark Blue: Trailer Brake
Trailer Connections
(C7/C8 Models Only)
If your vehicle has these trailer connections, they are
located at the rear of the cab for a tractor and at the rear
of the chassis when towing a trailer. There will be an
air connection and an electrical connection.
Be sure that the couplings to the trailer are made
correctly.
Air Connections
If you are not connecting the trailer air line connections
to another piece of equipment, be sure to replace
their protective caps.
Electrical Connections
This system is a seven-wire cable that will connect to
the trailer, supplying power to the trailer’s lighting
system. When not in use, it is stored in the trailer
air-hose storage bracket.
4-39

Engine Fan Noise
Your vehicle has a clutched engine cooling fan. When
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions, the clutch is not fully engaged. This improves
fuel economy and reduces fan noise. Under heavy
vehicle loading, trailer towing and/or high outside
temperatures, the fan speed increases when the clutch
engages. So you may hear an increase in fan noise.
This is normal and should not be mistaken as the
transmission slipping or making extra shifts. It is merely
the cooling system functioning properly. The fan will
slow down when additional cooling is not required and
the clutch disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch disengages.
Power Steering Fluid
SeeScheduled Maintenance on page 6-5to determine
when to check your power steering fluid.
How To Check Power Steering Fluid
Check your power steering fluid only when the engine is
warm. If the engine is not warm, you probably will not
get an accurate reading.
If the fluid level is between the MIN (Minimum) and
MAX (Maximum) marks, you have enough. If you need
fluid, add only enough of the proper fluid to bring it
in between the MIN and MAX marks.
If your power steering fluid level is low, this can cause
the brake or service brakes soon warning lights to come
on. In addition, the steering effort and emergency
brake distance could increase.
If either light remains on after you have added power
steering fluid to the proper level, then shut off the engine
for 10 seconds. This should reset the brake warning
lights. If one or both lights stay on, see “Hydraulic Brake
System Warning Lights” underBrake System Warning
Light on page 3-33for more information.
What to Use
To determine what kind of fluid to use, seePart C:
Recommended Fluids and Lubricants on page 6-33.
Notice:When adding power steering uid or
making a complete uid change, always use the
proper uid. Failure to use the proper uid can
cause leaks and damage hoses and seals.
5-47

GM Mobility Reimbursement
Program
This program, available to qualified applicants, can
reimburse you up to $1,000 of the cost of eligible
aftermarket adaptive equipment required for your vehicle,
such as hand controls or a wheelchair/scooter lift.
The offer is available for a very limited period of time
from the date of vehicle purchase/lease. For more
details, or to determine your vehicle’s eligibility, visit
gmmobility.com or call the GM Mobility Assistance
Center at 1-800-323-9935. Text telephone (TTY) users,
call 1-800-833-9935.
GM of Canada also has a Mobility Program.
Call 1-800-GM-DRIVE (463-7483) for details.
TTY users call 1-800-263-3830.
Roadside Assistance Program
GM Medium Duty Truck’s Roadside Assistance provides
stranded owners with towing service for disabled
vehicles.
This service combines the efforts of trained telephone
representatives with a network of GM Medium Duty
Truck’s dealer services.
Just dial GM Medium Duty Truck Roadside Assistance
at1-800-862-4389to reach a qualified representative
who can assist you in a repair or arrange a tow. Other
recommended services can also be arranged for
situations such as retrieving locked in keys, changing a
tire, or delivering gasoline, at a charge to the customer.
We also provide dealer information at no charge,
such as location of the nearest authorized medium duty
GM Truck dealer and their hours of operation.
Roadside Assistance is available 24 hours a day,
7 days a week, 365 days a year. Should you have
any questions about Roadside Assistance, call the
GM Medium Duty Truck Roadside Assistance Center or
contact your dealer.
7-5

Canadian Roadside Assistance
In Canada, Medium Duty trucks are not eligible
for Roadside Assistance services. However,
owners/operators who contact Roadside Assistance
by calling1-800-268-6800may have a tow arranged
for them at the owner/operator expense.
If a Medium Duty truck is towed to the nearest General
Motors dealership and the towing was necessary
due to failure of a warranted part, the dealer will accept
the towing charges and submit them as part of the
warranty claim.
Vehicle Data Collection and
Event Data Recorders
Your vehicle, like other modern motor vehicles, has a
number of sophisticated computer systems that
monitor and control several aspects of the vehicle’s
performance. Your vehicle uses on-board vehicle
computers to monitor emission control components to
optimize fuel economy, to monitor conditions for
airbag deployment and, if so equipped, to provide
anti-lock braking and to help the driver control the
vehicle in difficult driving situations.Some information may be stored during regular
operations to facilitate repair of detected malfunctions;
other information is stored only in a crash event by
computer systems, such as those commonly called
event data recorders (EDR).
In a crash event, computer systems, such as the Airbag
Sensing and Diagnostic Module (SDM) in your vehicle
may record information about the condition of the vehicle
and how it was operated, such as data related to
engine speed, brake application, throttle position, vehicle
speed, safety belt usage, airbag readiness, airbag
performance, and the severity of a collision. This
information has been used to improve vehicle crash
performance and may be used to improve crash
performance of future vehicles and driving safety. Unlike
the data recorders on many airplanes, these on-board
systems do not record sounds, such as conversation of
vehicle occupants.
7-6

If an Accident Occurs
Here is what to do if you are involved in an accident.
•Try to relax and then check to make sure you are all
right. If you are uninjured, make sure that no one else
in your vehicle, or the other vehicle, is injured.
•If there has been an injury, call 911 for help. Do not
leave the scene of an accident until all matters have
been taken care of. Move your vehicle only if its
position puts you in danger or you are instructed to
move it by a police officer.
•Give only the necessary and requested information
to police and other parties involved in the accident.
Do not discuss your personal condition, mental frame
of mind, or anything unrelated to the accident. This
will help guard against post-accident legal action.
•If you need roadside assistance, call GM Roadside
Assistance. SeeRoadside Assistance Program on
page 7-5for more information.
•If your vehicle cannot be driven, know where the
towing service will be taking it. Get a card from the
tow truck operator or write down the driver’s name,
the service’s name, and the phone number.
•Remove any valuables from your vehicle before it is
towed away. Make sure this includes your insurance
information and registration if you keep these items
in your vehicle.
•Gather the important information you will need from
the other driver. Things like name, address, phone
number, driver’s license number, vehicle license
plate, vehicle make, model and model year, Vehicle
Identification Number (VIN), insurance company and
policy number, and a general description of the
damage to the other vehicle.
•If possible, call your insurance company from the
scene of the accident. They will walk you through the
information they will need. If they ask for a police
report, phone or go to the police department
headquarters the next day and you can get a copy of
the report for a nominal fee. In some states with “no
fault” insurance laws, a report may not be necessary.
This is especially true if there are no injuries and both
vehicles are driveable.
•Choose a reputable collision repair facility for your
vehicle. Whether you select a GM dealer or a private
collision repair facility to fix the damage, make sure
you are comfortable with them. Remember, you will
have to feel comfortable with their work for a
long time.
•Once you have an estimate, read it carefully and
make sure you understand what work will be
performed on your vehicle. If you have a question,
ask for an explanation. Reputable shops welcome
this opportunity.
7-9