GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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Driving and Operating 287
effort to shift out of P (Park). See
“Torque Lock”underShifting Into
Park 0283.
{Warning
It is dangerous to get out of the
vehicle if the shift lever is not fully
in P (Park) with the parking brake
firmly set. The vehicle can roll.
Do not leave the vehicle when the
engine is running. If you have left
the engine running, the vehicle
can move suddenly. You or others
could be injured. To be sure the
vehicle will not move, even when
you are on fairly level ground,
always set the parking brake and
move the shift lever to P (Park).
See Shifting Into Park 0283 and
Driving Characteristics and
Towing Tips 0322.
{Warning
If you have four-wheel drive, the
vehicle will be free to roll —even
if the shift lever is in P (Park) —if
the transfer case is in N (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
N (Neutral). See Shifting Into
Park 0283.
R : Use this gear to back up.
Caution
Shifting to R (Reverse) while the
vehicle is moving forward could
damage the transmission. The
repairs would not be covered by
the vehicle warranty. Shift to
R (Reverse) only after the vehicle
is stopped. To rock the vehicle back and forth to
get out of snow, ice, or sand without
damaging the transmission, see
If
the Vehicle Is Stuck 0268.
N : In this position, the engine does
not connect with the wheels. To
restart when you are already
moving, use N (Neutral) only. Also,
use N (Neutral) when the vehicle is
being towed.
{Warning
Shifting into a drive gear while the
engine is running at high speed is
dangerous. Unless your foot is
firmly on the brake pedal, the
vehicle could move very rapidly.
You could lose control and hit
people or objects. Do not shift
into a drive gear while the engine
is running at high speed.
GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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292 Driving and Operating
as with ice or snow. While the
vehicle is at a stop, select M2 using
Range Selection Mode. This will
limit torque to the wheels and help
to prevent the tires from spinning.
Tow/Haul Mode
Vehicles with an automatic
transmission have a Tow/Haul
Mode. The Tow/Haul Mode adjusts
the transmission shift pattern to
reduce shift cycling. This provides
increased performance, vehicle
control, and enhanced transmission
and engine cooling when drivingdown steep hills or mountain
grades, towing, or hauling heavy
loads.
The selector button is on the end of
the shift lever. Turn the Tow/Haul
Mode on and off by pressing the
button. When the Tow/Haul Mode is
enabled, a light on the instrument
cluster will come on.
See
Tow/Haul Mode Light 0144 and
Hill and Mountain Roads 0266.
Also see “Tow/Haul Mode” under
Towing Equipment 0339.
Tow/Haul Mode Grade Braking
Tow/Haul Mode Grade Braking is
only enabled while the Tow/Haul
Mode is selected and the vehicle is
not in the Range Selection Mode.
See “Tow/Haul Mode” listed
previously and Manual Mode0289.
Tow/Haul Mode Grade Braking
assists in maintaining desired
vehicle speeds when driving on
downhill grades by using the engine
and transmission to slow the
vehicle. On vehicles with a gasoline engine,
to disable or enable Tow/Haul
Grade Braking within the current
ignition key cycle, press and hold
the Tow/Haul button for
five seconds. When the button is
released, the requested mode
change is made. A DIC message is
displayed. See
Transmission
Messages 0160.
On vehicles with a diesel engine,
Tow/Haul Mode Grade Braking can
be enabled or disabled by pressing
the Tow/Haul Mode button. Use the
exhaust brake and Tow/Haul Mode
for maximum grade braking.
See Towing Equipment 0339.
For other forms of grade braking,
see Automatic Transmission 0286
and Cruise Control 0306.
GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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294 Driving and Operating
N (Neutral) :Use only when the
vehicle needs to be towed. See
Recreational Vehicle Towing 0439
or Towing the Vehicle 0439.
2
m(Two-Wheel Drive High) : Use
this setting for driving on most
streets and highways. The front axle
is not engaged. This setting
provides the best fuel economy.
4
n(Four-Wheel Drive Low) : This
setting also engages the front axle
and delivers extra torque. Choose 4
nif driving off-road in deep sand,
deep mud, or deep snow, and while
climbing or descending steep hills.
When engaged, keep vehicle speed
below 72 km/h (45 mph).
4
m(Four-Wheel Drive High) : Use
this setting when extra traction is
needed. The front axle engages and
helps when driving on snowy or icy
roads, when off-roading, or when
plowing snow. The vehicle can be shifted between
2
mand 4mwhile the vehicle is
moving. In extremely cold weather,
it may be necessary to stop or slow
the vehicle to shift into 4
m.
Using the Manual Transfer Case
. Use quick motions to shift into or
out of 4
nor N (Neutral).
. Shifting may be harder when the
vehicle is cold, but will return to
normal once warmed up.
. Four-wheel drive reduces fuel
economy.
Shifting from 2
mto 4m
. Shifts can be made at any
vehicle speed.
. Shift in one continuous motion.
. Shifting while the vehicle is in
motion may require that
moderate force be applied to the
shift lever before 4
mcan be
engaged, especially in cold
weather. .
In extremely cold weather, it may
be necessary to slow or stop the
vehicle to shift.
. While in 4
m, the vehicle can be
driven at any posted legal speed
limit.
Shifting In or Out of 4
n
Caution
Shifting the transfer case into 4n
while moving at speeds faster
than 5 km/h (3 mph) may cause
premature wear to the transfer
case, and may cause the gears to
grind.
1. If possible, shift with the vehicle moving 5 km/h (3 mph)
or less.
2. Shift the transmission into N (Neutral).
3. Shift the transfer case shift lever in one continuous motion.
4. Shifting with the vehicle at a stop may be more difficult. It is
possible that the shift will not
GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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296 Driving and Operating
4n(Four-Wheel Drive Low) :This
setting engages the front axle and
delivers extra torque. Choose 4
nif
driving off-road in deep sand, deep
mud, or deep snow, and while
climbing or descending steep hills.
When engaged, keep vehicle speed
below 72 km/h (45 mph).
Shifting into 4
nwill turn Traction
Control and StabiliTrak off. See
Traction Control/Electronic Stability
Control 0303.
4
m(Four-Wheel Drive High) : Use
when extra traction is needed. The
front axle engages and helps when
driving on snowy or icy roads, when
off-roading, or when plowing snow.
The vehicle can be shifted from 2
m
to 4mwhile the vehicle is moving.
Shifting Into 4
m
Turn the knob to 4mat any speed
up to 121 km/h (75 mph), except
from 4
n. The indicator light will flash
while shifting and will remain on the
selected setting. Shifting Into 2
m
Turn the knob to 2mat any speed,
except when shifting from 4
n.
Shifting Into 4
n
When 4nis engaged, vehicle speed
should be kept below 72 km/h
(45 mph).
1. The ignition must be in ON/ RUN and the vehicle must be
stopped or moving less than
5 km/h (3 mph) with the
transmission in N (Neutral). It is
best for the vehicle to be
moving 1.6 to 3.2 km/h
(1 to 2 mph).
2. Turn the knob to 4
n. Wait for
the 4
nindicator light to stop
flashing before shifting the
transmission into gear.
If the transmission is in gear and/or
moving more than 5 km/h (3 mph),
the 4
nindicator light will flash for
30 seconds and not complete the
shift. After 30 seconds the transfer
case will shift to 4
m. Turn the knob to 4
mto see the indicator. With the
vehicle moving less than 5 km/h
(3 mph), and the transmission in
N (Neutral), attempt the shift again.
Shifting Out of 4
n
1. To shift out of 4nthe vehicle
must be stopped or moving
less than 5 km/h (3 mph) with
the transmission in N (Neutral)
and the ignition in ON/RUN.
It is best for the vehicle to be
moving 1.6 to 3.2 km/h
(1 to 2 mph).
2. Turn the knob to 4
mor 2m.
Wait for the 4
mor 2mindicator
light to stop flashing before
shifting the transmission
into gear.
If the transmission is in gear and/or
moving more than 5 km/h (3 mph),
the 4
mor 2mindicator light will flash
for 30 seconds, but will not complete
the shift. With the vehicle moving
less than 5 km/h (3 mph), and the
transmission in N (Neutral), attempt
the shift again.
GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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298 Driving and Operating
An indicator light on the knob shows
which setting the transfer case is in.
The N (Neutral) indicator is on the
face of the knob. If the light displays
momentarily when the ignition is in
ON/RUN, but does not stay on, the
knob may have been turned while
the vehicle was off. To see the
indicator, turn the knob to another
position so that it matches the
actual transfer case setting. If no
lights display, take the vehicle to
your dealer for service. An indicator
light flashes while shifting and until
the shift is complete.
If the transfer case cannot make a
requested shift, it will return to the
last chosen setting. Turn the knob
back to the previous transfer case
setting to see the indicator.
The settings are:
N (Neutral) :Use only when the
vehicle needs to be towed. See
Recreational Vehicle Towing 0439
or Towing the Vehicle 0439. 2m(Two-Wheel Drive High) :
Use
for driving on most streets and
highways. The front axle is not
engaged. This setting provides the
best fuel economy.
AUTO (Automatic Four-Wheel
Drive) : Use when road surface
traction conditions are variable.
When driving in AUTO, the front
axle is engaged, and the vehicle's
power is sent to the front and rear
wheels automatically based on
driving conditions. This setting
provides slightly lower fuel economy
than 2
m.
Do not use AUTO mode,
if equipped, to park on a steep
grade with poor traction such as ice,
snow, mud, or gravel. In AUTO
mode only the rear wheels will hold
the vehicle from sliding when
parked. If parking on a steep grade,
use 4
mto keep all four wheels
engaged. 4
m(Four-Wheel Drive High) :
Use
this position when extra traction is
needed, such as when driving on
snowy or icy roads, when
off-roading, or when plowing snow.
4
n(Four-Wheel Drive Low) : This
setting engages the front axle and
delivers extra torque. Choose 4
n
when driving off-road in deep sand,
deep mud, or deep snow, and while
climbing or descending steep hills.
Shifting into 4
nwill turn Traction
Control and StabiliTrak off. See
Traction Control/Electronic Stability
Control 0303.
Shifting Into 4
mor AUTO
Turn the knob to the 4
mor AUTO
position at any speed, except from 4
n. The indicator light will flash while
shifting and will remain on when the
shift is completed.
GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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348 Driving and Operating
A GM dealer may be able to
diagnose and repair problems with
the trailer. However, any diagnosis
and repair of the trailer is not
covered under the vehicle warranty.
Contact your trailer dealer for
assistance with trailer repairs and
trailer warranty information.
Trailer Sway
Control (TSC)
Vehicles with StabiliTrak have a
TSC feature. Trailer sway is
unintended side-to-side motion of a
trailer while being towed. If the
vehicle is towing a trailer and the
TSC detects that sway is increasing,
the vehicle brakes are selectively
applied at each wheel, to help
reduce excessive trailer sway. If the
vehicle is equipped with the
Integrated Trailer Brake Control
(ITBC) system, and the trailer has
the electric actuated brake system,
StabiliTrak may also apply the trailer
brakes.
If TSC is enabled, the Traction
Control System (TCS)/StabiliTrak
warning light will flash on theinstrument cluster. Vehicle speed
must be reduced. If trailer sway
continues, StabiliTrak can reduce
engine torque to help slow the
vehicle. See
Traction Control/
Electronic Stability Control 0303.
{Warning
Even if the vehicle is equipped
with TSC, trailer sway could result
in loss of control and the vehicle
could crash. If excessive trailer
sway is detected, slow down to a
safe speed. Check the trailer and
vehicle to help correct possible
causes. These could include an
improperly or overloaded trailer,
unrestrained cargo, improper
trailer hitch configuration,
excessive vehicle-trailer speed,
or improperly inflated or incorrect
vehicle or trailer tires. See Towing
Equipment 0339 for trailer ratings
and hitch setup
recommendations. Adding non-dealer accessories can
affect the vehicle performance. See
Accessories and
Modifications
0356.
GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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380 Vehicle Care
Caution (Continued)
freezing occurs, which could
damage the tank if it is
completely full.
Brakes
Disc brake pads have built-in wear
indicators that make a high-pitched
warning sound when the brake pads
are worn and new pads are needed.
The sound can come and go or be
heard all the time the vehicle is
moving, except when applying the
brake pedal firmly.
{Warning
The brake wear warning sound
means that soon the brakes will
not work well. That could lead to
a crash. When the brake wear
warning sound is heard, have the
vehicle serviced.
Caution
Continuing to drive with worn-out
brake pads could result in costly
brake repair.
Some driving conditions or climates
can cause a brake squeal when the
brakes are first applied or lightly
applied. This does not mean
something is wrong with the brakes.
Properly torqued wheel nuts are
necessary to help prevent brake
pulsation. When tires are rotated,
inspect brake pads for wear and
evenly tighten wheel nuts in the
proper sequence to torque
specifications in Capacities and
Specifications 0468.
Brake linings should always be
replaced as complete axle sets.
Brake Pedal Travel
See your dealer if the brake pedal
does not return to normal height,
or if there is a rapid increase in
pedal travel. This could be a sign
that brake service may be required.
Replacing Brake System Parts
Always replace brake system parts
with new, approved replacement
parts. If this is not done, the brakes
may not work properly. The braking
performance expected can change
in many other ways if the wrong
replacement brake parts are
installed or parts are improperly
installed.
Brake Fluid
The brake master cylinder reservoir
is filled with DOT 3 brake fluid. See
Engine Compartment Overview
0 358 for the location of the
reservoir.
GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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414 Vehicle Care
Tire Inspection
We recommend that the tires,
including the spare tire, if the
vehicle has one, be inspected
for signs of wear or damage at
least once a month.
Replace the tire if:
.The indicators at three or
more places around the tire
can be seen.
.There is cord or fabric
showing through the tire's
rubber.
.The tread or sidewall is
cracked, cut, or snagged
deep enough to show cord or
fabric.
.The tire has a bump, bulge,
or split.
.The tire has a puncture, cut,
or other damage that cannot
be repaired well because of
the size or location of the
damage.
Tire Rotation
Tires should be rotated every
12 000 km (7,500 mi). See
Maintenance Schedule0454.
Tires are rotated to achieve a
uniform wear for all tires. The
first rotation is the most
important.
Anytime unusual wear is
noticed, rotate the tires as soon
as possible, check for proper tire
inflation pressure, and check for
damaged tires or wheels. If the
unusual wear continues after the
rotation, check the wheel
alignment. See When It Is Time
for New Tires 0416 andWheel
Replacement 0421.
Use this rotation pattern when
rotating the tires if the vehicle
has single rear wheels.
Dual Tire Rotation
When the vehicle is new,
or whenever a wheel, wheel
bolt, or wheel nut is replaced,
check the wheel nut torque after
160, 1 600, and 10 000 km (100,
1,000, and 6,000 mi) of driving.
For proper torque and wheel nut
tightening information, see
“Removing the Flat Tire and
Installing the Spare Tire” under
Tire Changing 0424.