towing GMC SIERRA 2007 Owner's Manual

Seats and Restraint Systems
....................... 7
Front Seats
.............................................. 9
Rear Seats
............................................. 20
Safety Belts
............................................ 22
Child Restraints
...................................... 45
Airbag System
........................................ 83
Restraint System Check
....................... 104
Features and Controls
.............................. 107
Keys
..................................................... 109
Doors and Locks
.................................. 118
Windows
............................................... 124
Theft-Deterrent Systems
....................... 127
Starting and Operating Your Vehicle
..... 132
Mirrors
.................................................. 169
OnStar
®System
................................... 180
Universal Home Remote System
.......... 184
Storage Areas
...................................... 196
Sunroof
................................................ 200Instrument Panel
....................................... 203
Instrument Panel Overview
................... 206
Climate Controls
................................... 234
Warning Lights, Gages, and
Indicators
.......................................... 246
Driver Information Center (DIC)
............ 267
Audio System(s)
................................... 300
Driving Your Vehicle
................................. 373
Your Driving, the Road, and
Your Vehicle
..................................... 374
Towing
................................................. 439
Service and Appearance Care
.................. 483
Service
................................................. 486
Fuel
...................................................... 488
Checking Things Under the Hood
......... 496
Rear Axle
............................................. 538
Four-Wheel Drive
.................................. 539
Front Axle
............................................ 541
2007 GMC Sierra Owner ManualM
1

See “Safety Belts” and “Child Restraints” in the
Index for additional information about the
importance of proper restraint use.
{CAUTION:
If the airbag readiness light in the
instrument panel cluster ever comes on
and stays on, it means that something
may be wrong with the airbag system. If
this ever happens, have the vehicle
serviced promptly, because an adult-size
person sitting in the right front
passenger’s seat may not have the
protection of the airbag(s). SeeAirbag
Readiness Light on page 250for more on
this, including important safety
information.A thick layer of additional material, such as a
blanket or cushion, or aftermarket equipment such
as seat covers, seat heaters, and seat massagers
can affect how well the passenger sensing
system operates. You may want to consider not
using seat covers or other aftermarket equipment.
SeeAdding Equipment to Your Airbag-Equipped
Vehicle on page 102for more information
about modications that can affect how the system
operates.
{CAUTION:
Stowing of articles under the passenger’s
seat or between the passenger’s seat
cushion and seatback may interfere with
the proper operation of the passenger
sensing system.
101

Starting and Operating Your
Vehicle
New Vehicle Break-In
Notice:Your vehicle does not need an
elaborate break-in. But it will perform better in
the long run if you follow these guidelines:
Keep your speed at 55 mph (88 km/h)
or less for the rst 500 miles (805 km).
Do not drive at any one constant speed,
fast or slow, for the rst 500 miles
(805 km). Do not make full-throttle starts.
Avoid downshifting to brake, or slow,
the vehicle.
Avoid making hard stops for the rst
200 miles (322 km) or so. During this time
the new brake linings are not yet broken in.
Hard stops with new linings can mean
premature wear and earlier replacement.
Follow this breaking-in guideline every time
you get new brake linings.
Do not tow a trailer during break-in. See
Towing a Trailer on page 445for the trailer
towing capabilities of your vehicle and more
information.
Following break-in, engine speed and load can
be gradually increased.
132

When parked on a hill, especially when the vehicle
has a heavy load, you might notice an increase in
the effort to shift out of Park. See Torque Lock
(Automatic Transmission) underShifting Into
Park (P) on page 163for more information.
{CAUTION:
It is dangerous to get out of your vehicle
if the shift lever is not fully in PARK (P)
with the parking brake rmly set. Your
vehicle can roll.
Do not leave your vehicle when the engine
is running unless you have to. If you have
left the engine running, the vehicle can
move suddenly. You or others could be
injured. To be sure your vehicle will not
move, even when you are on fairly level
ground, always set your parking brake
and move the shift lever to PARK (P). See
Shifting Into Park (P) on page 163.Ifyou
are pulling a trailer, seeTowing a Trailer
on page 445.
{CAUTION:
If you have Four-Wheel Drive, your vehicle
will be free to roll — even if your shift lever
is in PARK (P) — if your transfer case is in
NEUTRAL. So, be sure the transfer case is
in a drive gear, Two-Wheel Drive High or
Four-Wheel Drive High or Four-Wheel Drive
Low — not in NEUTRAL. SeeShifting Into
Park (P) on page 163.
REVERSE (R):Use this gear to back up.
Notice:Shifting to REVERSE (R) while your
vehicle is moving forward could damage the
transmission. The repairs would not be covered
by your warranty. Shift to REVERSE (R) only
after your vehicle is stopped.
To rock your vehicle back and forth to get out of
snow, ice, or sand without damaging your
transmission, seeIf Your Vehicle is Stuck in Sand,
Mud, Ice, or Snow on page 422.
139

NEUTRAL (N):In this position, your engine does
not connect with the wheels. To restart when
you are already moving, use NEUTRAL (N) only.
Also, use NEUTRAL (N) when your vehicle is
being towed.
{CAUTION:
Shifting into a drive gear while your engine
is running at high speed is dangerous.
Unless your foot is rmly on the brake
pedal, your vehicle could move very
rapidly. You could lose control and hit
people or objects. Do not shift into a
drive gear while your engine is running
at high speed.
Notice:Shifting out of PARK (P) or
NEUTRAL (N) with the engine running at high
speed may damage the transmission. The
repairs would not be covered by your warranty.
Be sure the engine is not running at high
speed when shifting your vehicle.DRIVE (D):This position is for normal driving. It
provides the best fuel economy for your vehicle. If
you need more power for passing, and you are:
Going less than about 35 mph (55 km/h),
push your accelerator pedal about
halfway down.
Going about 35 mph (55 km/h) or more, push
the accelerator all the way down.
By doing this, the vehicle shifts down to the
next gear and has more power.
DRIVE (D) can be used when towing a trailer,
carrying a heavy load, driving on steep hills, or for
off-road driving. You might want to shift the
transmission to a lower gear selection if the
transmission shifts too often.
Downshifting the transmission in slippery road
conditions could result in skidding. See Skidding
underLoss of Control on page 389.
Your vehicle has a shift stabilization feature that
adjusts the transmission shifting to the current
driving conditions in order to reduce rapid upshifts
and downshifts.
140

This shift stabilization feature is designed to
determine, before making an upshift, if the engine
is able to maintain vehicle speed by analyzing
things such as vehicle speed, throttle position, and
vehicle load. If the shift stabilization feature
determines that a current vehicle speed cannot be
maintained, the transmission does not upshift
and instead holds the current gear. In some cases,
this could appear to be a delayed shift, however
the transmission is operating normally.
Your vehicle’s transmission uses adaptive shift
controls. Adaptive shift controls continually
compares key shift parameters to pre-programmed
ideal shifts stored in the transmissions computer.
The transmission constantly makes adjustments to
improve vehicle performance according to how the
vehicle is being used, such as with a heavy load or
when temperature changes. During this adaptive
shift control process, shifting might feel different as
the transmission determines the best settings.When temperatures are very cold, the Allison
Transmission®and Hydra-Matic®6-Speed
transmission’s gear shifting could be delayed
providing more stable shifts until the engine warms
up. Shifts could be more noticeable with a cold
transmission. This difference in shifting is normal.
MANUAL MODE (M):This position, is available
on vehicles with the Allison Transmission
®or
Hydra-Matic®6-Speed transmission. It lets drivers
select the range of gears appropriate for current
driving conditions. If your vehicle has this feature,
see Range Select Mode (Allison Transmission
®
or Hydra-Matic®6-Speed transmission) later in
this section.
THIRD (3):This position is also used for normal
driving. It reduces vehicle speed more than
DRIVE (D) without using the brakes. You might
choose THIRD (3) instead of DRIVE (D) when
driving on hilly, winding roads, when towing
a trailer, so there is less shifting between gears
and when going down a steep hill.
141

Range Selection Mode (Allison®or
Hydra-Matic®6-Speed Transmission)
Your vehicle may have a Range Selection Mode.
The Range Selection Mode helps control the
vehicle’s transmission and vehicle speed while
driving down hill or towing a trailer by letting
you select a desired range of gears.To use this feature, do the following:
1. Move the shift lever to the MANUAL
MODE (M).
2. Press the plus/minus buttons, located on the
steering column shift lever, to select the
desired range of gears for your current
driving conditions.
When MANUAL MODE (M) is selected a number
displays next to the M, indicating the current gear.
This number is the highest gear that can be used.
However, your vehicle can automatically shift to
lower gears as it adjusts to driving conditions. This
means that all gears below that number are
available. When FIFTH (5) is selected, FIRST (1)
through FIFTH (5) gears are automatically shifted
by the vehicle, but SIXTH (6) cannot be used until
the plus/minus button located on the steering
column lever is used to change to the gear.
143

The tow/haul mode adjusts the transmission shift
pattern to reduce shift cycling, providing
increased performance, vehicle control, and
transmission cooling when towing or hauling
heavy loads.
The selector button is located on the end of
the shift lever. Turn the tow/haul on and off by
pressing the button. When the tow/haul is on, a
light on the instrument panel cluster will come on.
SeeTow/Haul Mode Light on page 266for more
information.
Also see Tow Haul Mode underTowing a Trailer
on page 445for more information.Tow/Haul Mode (Allison Transmission®
or Hydra-Matic®6-Speed Automatic
Transmission)
If your vehicle has an Allison or Hydra-Matic®
6-speed automatic transmission®, it has a tow/haul
mode. The tow/haul mode adjusts the transmission
shift pattern to reduce shift cycling, providing
increased performance, vehicle control, and
transmission cooling when towing or hauling
heavy loads.
145

Turn the tow/haul mode on and off by pressing the
button, located on the end of the shift lever.
When the tow/haul is on, a light on the instrument
panel cluster will come on.
SeeTow/Haul Mode Light on page 266for more
information.
Also see “Tow Haul Mode” underTowing a Trailer
on page 445for more information.
Grade Braking (Allison Transmission®
or Hydra-Matic®6-Speed Automatic
Transmission)
The Grade Braking shift modes can be activated
by pressing the button on the end of the shift
control lever. While in Range Selection Mode,
Grade Braking is deactivated allowing the driver to
select a desired range of gears.Grade Braking is only active while the Tow/Haul
Mode is selected and you are not in the Range
Selection Mode. See “Tow/Haul Mode listed
previously andAutomatic Transmission Operation
on page 138for more information on the Range
Selection Mode. Grade Braking assists in
maintaining desired vehicle speeds when driving
on downhill grades by automatically implementing
a shift schedule that utilizes the engine and
transmission to slow the vehicle. This reduces
wear on the braking system and increases control
of the vehicle. Grade Braking monitors vehicle
speed, acceleration, engine torque and brake
pedal usage. Using this information, it detects
when the truck is on a downhill grade and
the driver desires to slow the vehicle by pressing
the brake. See the diesel supplement for
information on Cruise Grade Braking.
Also seeTowing a Trailer on page 445for more
information.
146

A Four-Wheel Drive
indicator light comes on
when you shift into
four-wheel drive and the
front axle engages.
SeeFour-Wheel-Drive
Light on page 265
Some delay between shifting and when the
indicator light comes on is normal.
Recommended Transfer Case Settings
Driving ConditionsTransfer Case Settings
2m4m4nN
Normal YES
Severe YES
Extreme YES
Vehicle in Tow* YES
*SeeRecreational Vehicle Towing on page 439
Towing Your Vehicle on page 439
Notice:Driving on clean, dry pavement in
four-wheel drive for an extended period of time
can cause premature wear on your vehicle’s
powertrain. Do not drive on clean, dry
pavement in Four-Wheel Drive for extended
periods of time.
4
n(Four-Wheel-Drive Low):This setting also
engages the front axle and delivers extra
torque. You may never need Four-Wheel-Drive
Low. It sends maximum power to all four wheels.
You might choose Four-Wheel-Drive Low if
you are driving off-road in deep sand, deep mud,
deep snow, and while climbing or descending
steep hills. When operating in Four-Wheel Low,
the gear ratio provides additional torque when
compared to Four-Wheel-Drive High. The
transmission gear shift feel is exaggerated.
148