
Exhaust System Check
Be alert for any changes in the sound of the exhaust
system or any smell of fumes. These are signs the
system may be leaking. Have it checked and/or repaired
at once. Refer toEngine Exhaust on page 2-37and
Running Your Engine While You Are Parked on
page 2-38.
Windshield Wipers and Washers Check
Check operation and condition of the wiper blades.
Check the flow of the washer spray.
Defroster Check
Move the control to the defrost symbol and the fan to HI
or the high symbol. Then check the airflow from the
ducts at the inside base of the windshield.
Mirrors and Sun Visors Check
Check that friction joints hold mirrors and sun visors in
place.
Seat Adjuster Check
When adjusting a manual seat, be sure seat adjusters
latch by attempting to move the seat after latching.
Lamps Check
Check panel lighting, warning lights, indicator lights and
interior lamps. On the outside, check: license plate
lamps, sidemarker lamps, reflectors or lights on outside
mirrors, headlamps, parking lamps, identification and
clearance lamps, taillamps, brake lamps, turn signals,
backup lamps and hazard warning flashers. Have
headlamp aim checked at once if beams seem
improperly aimed.
Glass, Mirrors, Lamps and/or
Re ectors Condition Check
Look for broken, scratched, dirty or damaged glass,
mirrors, lamps or reflectors that could reduce the view
or visibility or cause injury. Replace, clean or repair
promptly.
Door Latches Check
Check that doors close, latch and lock tightly. Check for
broken, damaged or missing parts that might prevent
tight latching.
6-27

Hood Latches Check
Check that the hood closes firmly. Check for broken,
damaged, loose or missing parts that might prevent tight
latching. Make sure the secondary latch (if equipped)
keeps the hood from opening all the way when the
primary latch is released.
Fluid Leaks Check
Check for fuel, coolant, oil or other fluid leaks by looking
at the surface beneath the vehicle after it has been
parked for awhile.
Underbody Inspection
Corrosive materials used for ice, snow removal and dust
control can collect on the underbody. If these materials
are not removed, accelerated corrosion (rust) can
occur on underbody parts such as fuel lines, frame, floor
pan and exhaust system. At least every spring, flush
these materials from the underbody with plain
water. Take care to clean well any areas where mud
and other debris can collect. Sediment packed in closed
areas of the frame should be loosened before being
flushed.
Engine Cover Check
Check that the cab’s engine cover and seal (if equipped)
are not torn or damaged. Be sure that the cover is
clamped down firmly to the floor.
At Least Once a Year
Key Lock Cylinders Service
Lubricate the key lock cylinders with the lubricant
specified in Part C.
Underbody Flushing Service
At least every spring, use plain water to flush any
corrosive materials from the underbody. Take care to
clean thoroughly any areas where mud and other debris
can collect.
Tractor Protection (Breakaway) Valve
Check
On air brake models, remove, disassemble, clean and
inspect the tractor protection (breakaway) valve.
6-28

Usage Fluid/Lubricant
Manual
Transmission
(Except ZF
6–Speed)Synthetic Manual Transmission Fluid
(GM Part No. U.S. 12345724, in
Canada 10953510).
Manual
Transmission
(ZF 6–Speed)TranSynd™ Synthetic Transmission
Fluid (GM Part No. U.S. 12378515,
in Canada 88900701).
Automatic
TransmissionSee the Allison
Transmission
®Operator’s Manual for
correct transmission fluid.
Key Lock
CylindersMulti-Purpose Lubricant, Superlube
(GM Part No. U.S. 12346241, in
Canada 10953474).
Chassis
LubricationChassis Lubricant (GM Part No. U.S.
12377985, in Canada 88901242) or
lubricant meeting requirements of
NLGI #2, Category LB or GC-LB.
Front Wheel
Bearing Grease
(Except Oil
Filled Hubs)Wheel bearing lubricant meeting
requirements of NLGI #2, Category
GC or GC-LB (GM Part No. U.S.
1051344, in Canada 993037).
Usage Fluid/Lubricant
Front Wheel
Bearing Grease
with Oil Filled
HubsSAE 75W-90 Synthetic Axle
Lubricant for Medium Duty Trucks
(GM Part No. U.S. 12345841, in
Canada 10953512t).
Rear Axle and
Rear HubsSAE 75W-90 Synthetic Axle
Lubricant for Medium Duty Trucks
(GM Part No. U.S. 12345841, in
Canada 10953512).
Rear Axle Shift
Motor LubricantRefrigerant Oil (GM Part No.U.S.
5416939, in Canada 10953496).
Propshafts and
SplinesWheel bearing lubricant meeting
requirements of NLGI #2, Category
GC or GC-LB (GM Part No. U.S.
1051344, in Canada 993037).
Cab — Door
Hinges and
LatchesMulti-Purpose Lubricant, Superlube
(GM Part No. U.S. 12346241, in
Canada 10953474).
Weatherstrip
ConditioningDielectric Silicone Grease (GM Part
No. U.S. 12345579, in Canada
992887).
Weatherstrip
SqueaksSynthetic Grease with Teflon,
Superlube (GM Part No. U.S.
12371287, in Canada 10953437).
6-30

Just dial GM Medium Duty Truck Roadside Assistance
at 1-800-862-4389 to reach a qualified representative
who can assist you in a repair or arrange a tow. 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, including weekends
and holidays. Should you have any questions about
Roadside Assistance, call the GM Medium Duty Truck
Roadside Assistance Center or contact your dealer.
Vehicle Data Collection and
Event Data Records
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 air bag
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 or near crash event by computer systems
commonly called event data recorders (EDR).In a crash or near crash event, computer systems, such
as the Air Bag Sensing and Diagnostic Module (SDM)
in your vehicle may record information about the
condition of the vehicle and how it was operated, such
as engine speed, brake applications, throttle position,
vehicle speed, safety belt usage, air bag readiness, air
bag performance data, 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.
To read this information, special equipment is needed
and access to the vehicle or the SDM is required.
GM will not access information about a crash event or
share it with others other than
•with the consent of the vehicle owner or, if the
vehicle is leased, with the consent of the lessee,
•in response to an official request of police or similar
government office,
•as part of GM’s defense of litigation through the
discovery process, or
•as required by law.
7-5

A
Accessory Power Outlets.................................3-17
Adding Equipment to Your Air Bag-Equipped
Vehicle.......................................................1-61
Adding Washer Fluid.......................................5-44
Additives, Fuel................................................. 5-7
Add-On Electrical Equipment............................5-86
Adjusting the Speakers
(Balance/Fade)............................3-47, 3-50, 3-54
Air Bag
Off Light.....................................................3-28
Readiness Light..........................................3-27
Air Bag System..............................................1-48
Adding Equipment to Your Air Bag-Equipped
Vehicle...................................................1-61
Air Bag Off Switch.......................................1-55
How Does an Air Bag Restrain?....................1-53
Servicing Your Air Bag-Equipped Vehicle.........1-60
What Makes an Air Bag Inflate?....................1-53
What Will You See After an Air Bag Inflates? . . 1-54
When Should an Air Bag Inflate?...................1-53
Where Are the Air Bags?..............................1-52
Air Brake.......................................................2-35
Air Brake System Warning Light........................3-33
Air Brake Systems..........................................5-50
Air Cleaner/Filter, Engine.................................5-30
Air Conditioning System...................................5-67Air Connections..............................................4-36
Air Dryer.......................................................5-50
Air Pressure Gage..........................................3-44
Air Shift Control (Automatic Transmission)..........2-27
Air Suspension...............................................2-27
Air Suspension Seats........................................ 1-6
Airbag Sensing and Diagnostic Module (SDM)...... 7-5
All Overseas Locations...................................... 7-4
Allison Transmission
®External Filters...............5-100
Aluminum or Chrome-Plated Wheels..................5-82
AM ...............................................................3-57
AM-FM Radio.................................................3-46
Antenna, Fixed Mast.......................................3-59
Anti-lock Brake System (ABS)............................ 4-7
Anti-Lock Brake, System Warning Light..............3-34
Anti-Lock Brakes, Trailer System
Warning Light.............................................3-35
Appearance Care............................................5-76
Care of Safety Belts....................................5-79
Chemical Paint Spotting...............................5-83
Cleaning the Inside of Your Vehicle................5-77
Cleaning the Outside of Your Vehicle..............5-80
Finish Damage............................................5-83
Sheet Metal Damage...................................5-82
Underbody Maintenance...............................5-83
Vehicle Care/Appearance Materials................5-84
Weatherstrips..............................................5-79
Ashtrays........................................................3-18
1

Care of
Safety Belts................................................5-79
Your Cassette Tape Player............................3-57
Your CD Player...........................................3-59
Your CDs ...................................................3-59
Cassette Tape Messages.................................3-52
CD Adapter Kits.............................................3-52
Center Console Storage Area...........................2-42
Center Passenger Position, Safety Belts.............1-22
Charging System Light....................................3-30
Chassis Lubrication.........................................5-51
Check
Engine Light...............................................3-37
Gages Warning Light...................................3-42
Checking Coolant............................................5-34
Checking Engine Oil................................5-21, 5-25
Checking Things Under the Hood......................5-18
Checking Your Restraint Systems......................1-61
Chemical Paint Spotting...................................5-83
Child Restraints
Child Restraint Systems...............................1-33
Infants and Young Children...........................1-29
Older Children.............................................1-27
Securing a Child Restraint in a Rear
Outside Seat Position...............................1-39
Securing a Child Restraint in the Center
Rear Seat Position (Crew Cab
®) or Center
Front Position..........................................1-41Child Restraints (cont.)
Securing a Child Restraint in the Right
Front Seat Position...................................1-43
Top Strap...................................................1-38
Where to Put the Restraint...................1-35, 1-37
Chime Level Adjustment..................................3-59
Chugger-Snubber Lock-Out Feature.................... 1-7
Cigarette Lighter.............................................3-18
Cleaning
Inside of Your Vehicle..................................5-77
Outside of Your Vehicle................................5-80
Underbody Maintenance...............................5-83
Weatherstrips..............................................5-79
Cleaning Exterior Lamps/Lenses.......................5-80
Cleaning Fabric/Carpet....................................5-77
Cleaning Glass Surfaces..................................5-79
Cleaning Interior Plastic Components.................5-79
Cleaning the Top of the
Instrument Panel.........................................5-79
Cleaning Vinyl................................................5-78
Climate Control System...................................3-19
Outlet Adjustment........................................3-22
Rear Heating System...................................3-23
Clutch Brake (Vehicles with Non-Synchronized
Transmission)..............................................2-32
Clutch Pedal Free Travel.................................5-51
Cold Weather Starting (Diesel Engine)...............2-20
Cold Weather Starting
(Caterpillar
®Diesel).....................................2-15
3

Compact Disc Messages..................................3-56
Control of a Vehicle.......................................... 4-5
Coolant
Engine Temperature Gage............................3-35
Heater, Engine............................................2-23
Low Warning Light.......................................3-36
Surge Tank Pressure Cap.............................5-35
Cooling System..............................................5-38
Cooling System Capacity.................................5-94
Cruise Control................................................3-10
Current and Past Model Order Forms.................. 7-8
Customer Assistance Information
Customer Assistance for Text Telephone
(TTY) Users.............................................. 7-3
Customer Assistance Offices........................... 7-3
Customer Satisfaction Procedure..................... 7-2
Reporting Safety Defects to General Motors...... 7-7
Reporting Safety Defects to the Canadian
Government.............................................. 7-7
Reporting Safety Defects to the United
States Government.................................... 7-6
Roadside Assistance Program......................... 7-4
Service Publications Ordering Information......... 7-7
D
Daytime Running Lamps..................................3-14
Daytime Running Lamps Indicator Light.............3-41
Defensive Driving............................................. 4-2Defogging and Defrosting.................................3-20
Defroster Check..............................................6-27
Diesel Engine
Exhaust Brake............................................2-25
Fuel............................................................ 5-8
Starting......................................................2-14
Starting Your DURAMAX™...........................2-19
Diesel Engine Warm-Up...................................2-16
Differential Lock Control, Inter-Axle....................4-10
Differential Lock Control, Rear Axle...................4-10
Differential Lock Indicator Light.........................3-40
Doing Your Own Service Work........................... 5-4
Dome Lamps.................................................3-15
Door
Locks.......................................................... 2-6
Power Door Locks......................................... 2-7
Door Latches Check........................................6-27
Double-Clutching.............................................2-30
Driver
Position, Safety Belt.....................................1-13
Driving
At Night.....................................................4-17
City...........................................................4-21
Defensive..................................................... 4-2
Drunken....................................................... 4-2
Freeway.....................................................4-22
Hill and Mountain Roads..............................4-23
In Rain and on Wet Roads...........................4-18
Winter........................................................4-25
4

I
If No Steam Is Coming From Your Engine..........5-37
If Steam Is Coming From Your Engine...............5-36
If You Are Caught in a Blizzard.........................4-27
If You Are Stuck in Sand, Mud, Ice or Snow.......4-29
If Your Diesel Engine Won’t Start......................2-20
Ignition Positions.............................................2-12
Illuminated Entry.............................................3-16
Infants and Young Children, Restraints...............1-29
Inflation - Tire Pressure...................................5-68
Instrument Panel
Cluster.......................................................3-24
Overview..................................................... 3-4
Switchbank.................................................3-16
Instrument Panel Brightness Control..................3-15
Instrument Panel Fuse Block............................5-88
Inter-Axle Differential Lock Control.....................4-10
Interior Lamps................................................3-15
J
Jump Starting.................................................5-56
K
Key Lock Cylinders Service..............................6-28
Keyless Entry System....................................... 2-3
Keys............................................................... 2-2
L
Lamps
Exterior......................................................3-13
Interior.......................................................3-15
Lamps Check.................................................6-27
Lap Belt........................................................1-22
Lap-Shoulder Belt...........................................1-13
Light
Air Bag Off .................................................3-28
Air Bag Readiness.......................................3-27
Anti-Lock Brake System Warning...................3-34
Brake System Warning.................................3-31
Change Engine Oil......................................3-39
Charging System.........................................3-30
Check Gages Warning.................................3-42
Daytime Running Lamps Indicator..................3-41
8