automatic transmission GMC SIERRA 2005 Owner's Guide

Remember: Anti-lock does not change the time you
need to get your foot up to the brake pedal or always
decrease stopping distance. If you get too close to
the vehicle in front of you, you will not have time to apply
your brakes if that vehicle suddenly slows or stops.
Always leave enough room up ahead to stop, even
though you have anti-lock brakes.
Using Anti-Lock
Do not pump the brakes. Just hold the brake pedal
down rmly and let anti-lock work for you. You may feel
the brakes vibrate, or you may notice some noise,
but this is normal.
Braking in Emergencies
With anti-lock, you can steer and brake at the same
time. In many emergencies, steering can help you more
than even the very best braking.
Traction Assist System (TAS)
Your vehicle may have a Traction Assist System (TAS)
that limits wheel spin. This is especially useful in
slippery road conditions. The system operates only if it
senses that one or both of the rear wheels are
spinning or beginning to lose traction. When this
happens, the system reduces engine power to limit
wheel spin.The traction control system is enabled every time your
vehicle is started. The system will activate if it senses
that any of the wheels are spinning or beginning to lose
traction.
You may hear or feel the system working or notice a
lack of accelerator response, but this is normal.
The Traction Assist System may operate on dry roads
under some conditions. When this happens, you
may notice a reduction in acceleration. This is normal
and doesn’t mean there’s a problem with your vehicle.
Examples of these conditions include a hard
acceleration in a turn, an abrupt upshift or downshift of
the transmission or driving on rough roads.
If your vehicle is in cruise control when the TAS begins
to limit wheel spin, the cruise control will automatically
disengage. When road conditions allow you to safely
use it again, you may re-engage the cruise control.
SeeCruise Control on page 3-10.
When the traction off light
is on, the TAS is off and
will not limit wheel
spin. Adjust your driving
accordingly.
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The traction off light will come on under the following
conditions:
The Traction Assist System is turned off, either by
pressing the TAS on/off button, located on the
instrument panel, or by turning off the automatic
engagement feature of the TAS.
The transmission is in FIRST (1); TAS will not
operate in this gear. This is normal.
The vehicle is driven on an extremely rough road.
When the vehicle leaves the rough surface, slows
down or stops, the light will go off and TAS will turn
on again. This is normal.
A Traction Assist System, Anti-Lock Brake System
or engine-related problem has been detected and
the vehicle needs service.
If the vehicle has been driven with the TAS system
on for long periods of time, or if the vehicle has
gone through many several high speed braking
maneuvers the system may be automatically
disabled. The system will automatically re-enable
after approximately two minutes of not using
the brakes.SeeTraction Off Light on page 3-41.
The Traction Assist System, as delivered from the
factory, will automatically come on whenever you start
your vehicle. To limit wheel spin, especially in
slippery road conditions, you should always leave the
system on. But you can turn the TAS off if you ever need
to. You should turn the TAS off if your vehicle ever
gets stuck in sand, mud or snow and rocking the vehicle
is required. SeeRocking Your Vehicle to Get It Out
on page 4-48andIf You Are Stuck: In Sand, Mud, Ice
or Snow on page 4-48.
To turn the system on or
off press the TAS on/off
button located on the
instrument panel.
If you used the button to turn the system off, the traction
off light will come on and stay on. You can turn the
system back on at any time by pressing the button
again. The traction off light should go off.
4-9

If desired, for a vehicle with QUADRASTEER™, you
can change the TAS automatic engagement feature so
that the system will not come on automatically when
the engine is started. To do so:
1. Park the vehicle with the ignition off and the
transmission in PARK (P) for an automatic
transmission, or in gear for a manual transmission.
2. Turn the ignition to RUN; do not start the engine.
3. Apply the brake pedal, shift into NEUTRAL (N),
press the accelerator pedal to the oor, then
press the TAS on/off button and hold it down for at
least six seconds.
4. Release the TAS button and both pedals.
5. Turn off the ignition and wait a few seconds.
The next time you start your vehicle, the TAS will not
automatically come on. You can restore the automatic
feature by repeating the same procedure. Whether
the TAS is set to come on automatically or not, you can
always turn the system on or off by pressing the TAS
on/off button.Manual Selectable Ride
The main function of this system is to provide superior
ride comfort while trailering or fully loaded, as well
as for unloaded driving. This system also helps
to provide:
Improved trailering stability
Improved handling response when trailering or fully
loaded
This button is located
on the center of the
instrument panel near
the radio.
Press it to activate the selectable ride setting as
desired. An indicator light near the button will illuminate
whenever the system is active.
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Dinghy Towing
Two-Wheel-Drive Vehicles
Notice:If you tow your vehicle with all four wheels
on the ground, the drivetrain components could
be damaged. The repairs would not be covered by
your warranty. Do not tow your vehicle with all
four wheels on the ground.
Two-wheel-drive vehicles should not be towed with all
four wheels on the ground. Two-wheel-drive
transmissions have no provisions for internal lubrication
while being towed.
Four-Wheel-Drive Vehicles Equipped with
Transfer Case (NP1, NP2 and NP8)
Use the following procedure to tow your vehicle:
1. Shift an automatic transmission to PARK (P), or a
manual transmission to FIRST (1).
2. Turn the engine off, but leave the ignition on.
3. Firmly set the parking brake.
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4. Securely attach the vehicle being towed to the
tow vehicle.
{CAUTION:
Shifting a four-wheel-drive vehicle’s transfer
case into NEUTRAL can cause your vehicle to
roll even if the transmission is in Park (P) for
an automatic transmission, or if your vehicle is
in gear, for a manual transmission. You or
others could be injured. Make sure the parking
brake is rmly set before you shift the transfer
case to NEUTRAL.
5. Shift the transfer case to NEUTRAL. See
Four-Wheel Drive on page 2-37for the proper
procedure to select the neutral position for
your vehicle.
6. Release the parking brake only after the vehicle
being towed is rmly attached to the towing
vehicle.
7. Turn the ignition off and leave the steering column
unlocked.
Dolly Towing
Front Towing (Front Wheels Off
the Ground)
Two-Wheel-Drive Vehicles
Notice:If you tow a two-wheel-drive vehicle with
the rear wheels on the ground, the transmission
could be damaged. The repairs would not be
covered by your warranty. Never tow your vehicle
with the rear wheels on the ground.
Two-wheel-drive vehicles should not be towed with the
rear wheels on the ground. Two-wheel-drive
transmissions have no provisions for internal lubrication
while being towed.
To dolly tow a two-wheel-drive vehicle, you must tow
the vehicle with the rear wheels on the dolly. See “Rear
Towing (Rear Wheels Off the Ground)” later in this
section for more information.
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Four-Wheel-Drive Vehicles
Use the following procedure to tow your vehicle:
1. Drive the vehicle up onto the tow dolly.
2. Shift an automatic transmission to PARK (P), or a
manual transmission to FIRST (1).
3. Turn the engine off, but leave the ignition on.4. Firmly set the parking brake.
5. Securely attach the vehicle being towed to
the tow dolly.
{CAUTION:
Shifting a four-wheel-drive vehicle’s transfer
case into NEUTRAL can cause your vehicle to
roll even if the transmission is in Park (P) for
an automatic transmission, or if your vehicle is
in gear, for a manual transmission. You or
others could be injured. Make sure the parking
brake is rmly set before you shift the transfer
case to NEUTRAL.
6. Shift the transfer case to NEUTRAL. See
Four-Wheel Drive on page 2-37for the proper
procedure to select the neutral position for
your vehicle.
7. Release the parking brake only after the vehicle
being towed is rmly attached to the towing
vehicle.
8. Turn the ignition off and lock the steering column.
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Rear Towing (Rear Wheels Off
the Ground)
Two-Wheel-Drive Vehicles
Use the following procedure to tow your vehicle from
the rear:
1. Drive the vehicle onto the dolly.
2. Firmly set the parking brake. SeeParking Brake on
page 2-48.
3. Put an automatic transmission in PARK (P) or a
manual transmission in FIRST (1).
4. Follow the dolly manufacturer’s instructions to
attach and secure the vehicle being towed to
the dolly and then the loaded dolly to the tow
vehicle. Make sure the wheels are straight
before towing.
For manual transmission vehicles, make sure the
wheels are straight before proceeding to the
next steps. On automatic transmission vehicles, use
an adequeate clamping device to ensure that the
front wheels are locked into the straight position.
5. Release the parking brake only after the vehicle
being towed is rmly attached to the tow vehicle.
6. Turn the ignition to LOCK.
Four-Wheel-Drive Vehicles
Use the following procedure to tow your vehicle from
the rear:
1. Drive the vehicle onto the dolly.
2. Firmly set the parking brake. SeeParking Brake on
page 2-48.
3. Put an automatic transmission in PARK (P) or a
manual transmission in FIRST (1).
4. Follow the dolly manufacturer’s instructions to
attach and secure the vehicle being towed to
the dolly and then the loaded dolly to the tow
vehicle.
For manual transmission vehicles, make sure the
wheels are straight before proceeding to the
next steps. On automatic transmission vehicles, use
an adequeate clamping device to ensure that the
front wheels are locked into the straight position.
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{CAUTION:
Shifting a four-wheel-drive vehicle’s transfer
case into NEUTRAL can cause your vehicle to
roll even if the transmission is in Park (P) for
an automatic transmission, or if your vehicle is
in gear, for a manual transmission. You or
others could be injured. Make sure the parking
brake is rmly set before you shift the transfer
case to NEUTRAL.
5. Shift the transfer case to NEUTRAL. See
Four-Wheel Drive on page 2-37.
6. Release the parking brake only after the vehicle
being towed is rmly attached to the tow vehicle.
7. Turn the ignition to LOCK.
Trailer Recommendations
You must subtract your hitch loads from the CWR for
your vehicle. Weigh your vehicle with the trailer
attached, so that you won’t go over the GVWR or
GAWR. If you are using a weight-distributing hitch,
weigh the vehicle without the spring bars in place.
You’ll get the best performance if you spread out the
weight of your load the right way, and if you choose the
correct hitch and trailer brakes.
For more information, seeTowing a Trailer on
page 4-68.
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Then, during the rst 500 miles (800 km) that you
tow a trailer, don’t drive over 50 mph (80 km/h)
and don’t make starts at full throttle. This helps your
engine and other parts of your vehicle wear in at
the heavier loads.
If you have an automatic transmission, you can tow
in DRIVE (D). You may want to shift the
transmission to THIRD (3) or, if necessary, a lower
gear selection if the transmission shifts too often,
such as under heavy loads and/or hilly conditions.
If you have a manual transmission and you are
towing a trailer, it’s better not to use the highest
gear. SeeTow/Haul Mode Light on page 3-49.
Three important considerations have to do with weight:
The weight of the trailer
The weight of the trailer tongue
The weight on your vehicle’s tires
Tow/Haul Mode
Tow/Haul is a feature on automatic transmission
equipped vehicles that assists when pulling a heavy
trailer or a large or heavy load. Tow/Haul mode adjusts
the transmission’s shift pattern to reduce shift cycling
(rapid up and downshifts/gear hunting), providing
increased performance, vehicle control, and transmission
cooling when towing or hauling heavy loads.Automatic transmission equipped vehicles are provided
with a button at the end of the shift lever which when
pressed enables Tow/Haul. When the button is pressed,
a light on the instrument panel will illuminate to
indicate that Tow/Haul has been selected. Tow/Haul
may be turned off by pressing the button again, at which
time the indicator light on the instrument panel will
turn off. The vehicle will automatically turn off Tow/Haul
every time it is started.
Tow/Haul is designed to be most effective when the
vehicle and trailer combined weight is at least 75 percent
of the vehicle’s Gross Combined Weight Rating (GCWR).
See “Weight of the Trailer” later in the section. Tow/Haul
is most useful under the following driving conditions:
When pulling a heavy trailer or a large or heavy load
through rolling terrain.
When pulling a heavy trailer or a large or heavy load
in stop and go traffic.
When pulling a heavy trailer or a large or heavy load
in busy parking lots where improved low speed
control of the vehicle is desired.
4-69

Passing
You’ll need more passing distance up ahead when
you’re towing a trailer. And, because you’re a good deal
longer, you’ll need to go much farther beyond the
passed vehicle before you can return to your lane.
Backing Up
Hold the bottom of the steering wheel with one hand.
Then, to move the trailer to the left, just move that hand
to the left. To move the trailer to the right, move your
hand to the right. Always back up slowly and, if possible,
have someone guide you.
Making Turns
Notice:Making very sharp turns while trailering
could cause the trailer to come in contact with the
vehicle. Your vehicle could be damaged. Avoid
making very sharp turns while trailering.
When you’re turning with a trailer, make wider turns
than normal. Do this so your trailer won’t strike
soft shoulders, curbs, road signs, trees or other objects.
Avoid jerky or sudden maneuvers. Signal well in
advance.
Turn Signals When Towing a Trailer
The arrows on your instrument panel will ash whenever
you signal a turn or lane change. Properly hooked up,
the trailer lamps will also ash, telling other drivers
you’re about to turn, change lanes or stop.
When towing a trailer, the arrows on your instrument
panel will ash for turns even if the bulbs on the trailer
are burned out. Thus, you may think drivers behind
you are seeing your signal when they are not. It’s
important to check occasionally to be sure the trailer
bulbs are still working.
Driving On Grades
Reduce speed and shift to a lower gearbeforeyou start
down a long or steep downgrade. If you don’t shift
down, you might have to use your brakes so much that
they would get hot and no longer work well.
If you have an automatic transmission, you can tow in
DRIVE (D). You may want to shift the transmission
to a lower gear selection if the transmission shifts too
often (e.g., under heavy loads and/or hilly conditions).
You may also want to activate the tow/haul mode if
the transmission shifts too often. SeeTow/Haul Mode
Light on page 3-49.
4-89