tow GMC SIERRA 2004 User Guide

How long should you keep the coolant heater plugged
in? The answer depends on the outside temperature, the
kind of oil you have, and some other things. Instead
of trying to list everything here, we ask that you contact
your dealer in the area where you'll be parking your
vehicle. The dealer can give you the best advice for that
particular area.
Automatic Transmission Operation
If your vehicle is equipped with an automatic
transmission, it features an electronic shift position
indicator within the instrument panel cluster. This display
must be powered anytime the shift lever is capable of
being moved out of PARK (P). See
Fuses and
Circuit Breakers on page 5-126.
There are several different positions for your shift lever.
PARK (P):This position locks your rear wheels. It's
the best position to use when you start your engine
because your vehicle can't move easily. If your vehicle
is equipped with the Allison
žTransmission, use
PARK (P) for stationary operation of the Power Takeoff
(PTO), if equipped.
{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 2-49
. If you are pulling a trailer, see
Towing a Trailer on page 4-70.
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{CAUTION:
If you have four-wheel drive, your vehicle will be
free to roll Ð even if your shift lever is in PARK
(P) Ð if your transfer case is in NEUTRAL. So,
be sure the transfer case is in a drive gear,
two-wheel high (2H) or four-wheel high (4H) or
four-wheel low (4L) Ð not in NEUTRAL. See
Shifting Into Park (P) on page 2-49
REVERSE (R):Use this gear to back up. If your vehicle
is equipped with the Allison Transmissionž, the R
may blink on the PRNDL if the shift inhibitor is active.
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,
see If You Are Stuck: In Sand, Mud, Ice or Snow on
page 4-51.NEUTRAL (N):In this position, your engine doesn't
connect with the wheels. To restart when you're 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.
2-27

DRIVE (D):This position is for normal driving. If you
need more power for passing, and you're:
·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.
You'll shift down to the next gear and have 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 may want to shift the transmission to THIRD (3)
or, if necessary, a lower gear selection if the
transmission shifts too often.
Notice:Extended idling for more than ®ve minutes
in DRIVE (D) on vehicles equipped with the Allison
Transmission may cause transmission overheating
and damage. Always put the gearshift lever in
PARK (P) if idle time is longer than ®ve minutes.
If your vehicle is equipped with the Allison
ž
Transmission, it will initially attain ®rst range when
DRIVE (D) is selected. As vehicle speed increases, the
transmission will upshift automatically through each
available range up to FIFTH (5). As the vehicle slows,
the transmission will downshift automatically.
THIRD (3):This position is also used for normal driving,
however it offers more power and lower fuel economy
than DRIVE (D).SECOND (2):This position gives you more power but
lower fuel economy. You can use SECOND (2) on
hills. It can help control your speed as you go down
steep mountain roads, but then you would also want to
use your brakes off and on.
If you manually select SECOND (2) in a light duty
automatic transmission, the transmission will drive in
second gear. You may use this feature for reducing the
speed of the rear wheels when you are trying to start
your vehicle from a stop on slippery road surfaces.
FIRST (1):This position gives you even more power
(but lower fuel economy) than SECOND (2). You
can use it on very steep hills, or in deep snow or mud.
If the selector lever is put in FIRST (1) while the
vehicle is moving forward, the transmission won't shift
into ®rst gear until the vehicle is going slowly enough.
Notice:Spinning the tires or holding the vehicle in
one place on a hill using only the accelerator
pedal may damage the transmission. If you are
stuck, do not spin the tires. When stopping on a hill,
use the brakes to hold the vehicle in place.
On cold days, approximately 32ÉF (0ÉC) or colder, your
transmission is designed to shift differently until the
engine reaches normal operating temperature. This is
intended to improve heater performance.
2-28

Tow/Haul Mode
(Automatic Transmission)
Your vehicle may be equipped with a Tow/Haul mode.
The selector button is located on the end of the
column shift lever. You can use this feature to assist
when towing or hauling a heavy load. Turn Tow/Haul on
and off by pressing the button until the Tow/Haul
indicator light illuminates on the instrument panel. See
ªTow/Haul Mode²under
Towing a Trailer on page 4-70for more information.
Overdrive Disable
(Allison Transmissionž)
If your vehicle has an Allison Transmissionžyou may
have the overdrive disable feature. The overdrive disable
feature prevents the transmission from shifting into
®fth (5) gear. The selector button is located on the end of
the column shift lever. You can turn overdrive disable on
and off by pressing and holding the button at the end of
the column shift lever until the indicator light, on the
instrument panel, illuminates.
2-29

If your vehicle has both Tow/Haul and overdrive disable
tap the button once to enable or disable Tow/Haul, and
press and hold the button to enable or disable overdrive
disable.
Manual Transmission Operation
Five-Speed
(VORTECŸ 6000 V8 Engine)
Here's how to operate your
transmission.
FIRST (1) is intended only for heavy loads or trailer
towing and is not recommended for normal driving.
During the ®rst 500 miles (805 km) of vehicle use, start
your vehicle moving in FIRST (1). This allows clutch
components to break-in properly.FIRST (1):Press the clutch pedal and shift into
FIRST (1). Then, slowly let up on the clutch pedal as
you press the accelerator pedal. Shift into FIRST (1)
only when the vehicle is below 5 mph (8 km/h). If you try
to shift down into FIRST (1) at excessive vehicle
speeds, the shift lever will not move into FIRST (1) until
vehicle speed is reduced.
SECOND (2):Press the clutch pedal and shift into
SECOND (2). Then, slowly let up on the clutch pedal as
you press the accelerator pedal.
You can shift into SECOND (2) when you're going less
than 20 mph (32 km/h). If you've come to a complete
stop and it's hard to shift into SECOND (2), put the shift
lever into NEUTRAL and let up on the clutch. Press
the clutch pedal back down. Then shift into
SECOND (2). If you try to downshift into SECOND (2) at
excessive vehicle speeds, the shift lever will not move
into the SECOND (2) position until the vehicle speed
is reduced.
THIRD (3):Press the clutch pedal and shift into
THIRD (3). Then, slowly let up on the clutch pedal as
you press the accelerator pedal.
2-30

THIRD (3), FOURTH (4) and FIFTH (5):Shift into
THIRD (3), FOURTH (4) and FIFTH (5) the same way
you do for SECOND (2). Slowly let up on the clutch
pedal as you press the accelerator pedal.
To stop, let up on the accelerator pedal and press the
brake pedal. Just before the vehicle stops, press
the clutch pedal and the brake pedal, and shift to
NEUTRAL.
NEUTRAL:Use this position when you start or idle
your engine.
REVERSE (R):To back up, ®rst press down the clutch
pedal. Wait for the vehicle to stop moving and then,
shift into REVERSE (R). Let up on the clutch pedal
slowly while pressing the accelerator pedal.
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.
Also, use REVERSE (R), along with the parking brake,
when turning off your engine and parking your
vehicle.
Six-Speed (VORTECŸ 8100 V8 and
DURAMAXŸ 6600 V8 Engines)
Here's how to operate your
transmission.
This six-speed pattern is unique to GM manual
transmissions. The transmission always repositions the
shift lever to NEUTRAL, which is located between
FOURTH (4) and FIFTH (5) gear.
To prevent unintentional gear selections, additional
force is required to move the shift lever into
REVERSE (R) or FIRST (1). Use FIRST (1) when trailer
towing, driving with payload in the pickup box or
launching on a grade. Otherwise, start in SECOND (2)
gear. Only shift into FIRST (1) when the vehicle has
stopped moving.
2-32

Recommended Transfer Case Settings
Transfer Case Settings
Driving Conditions 2HI 4HI 4LO N
Normal YES
Severe YES
Extreme YES
Vehicle in Tow* YES
*See
Recreational Vehicle Towing on page 4-54orTowing Your Vehicle on page 4-53for further
information.
An indicator on the bezel near the lever shows you the
transfer case settings:
2-Wheel High (2HI):This setting is used for driving in
most street and highway situations. Your front axle
is not engaged in two-wheel drive. This setting
also provides the best fuel economy.
4-Wheel High (4HI):Use 4HI when you need extra
traction, such as on snowy or icy roads or in most
off-road situations. This setting also engages your front
axle to help drive your vehicle. This is the best setting
to use when plowing snow.
{CAUTION:
Shifting the transfer case to NEUTRAL can
cause your vehicle to roll even if the
transmission is in PARK (P), or if you have a
manual transmission, even if you are in gear.
You or someone else could be seriously
injured. Be sure to set the parking brake
before placing the transfer case in NEUTRAL.
See
Parking Brake on page 2-48.
2-37

NEUTRAL (N):Shift to this setting only when your
vehicle needs to be towed. SeeRecreational Vehicle
Towing on page 4-54orTowing Your Vehicle on
page 4-53.
4-Wheel Low (4L0):This setting also engages your
front axle and delivers extra torque. You may never
need 4LO. It sends maximum power to all four wheels.
You might choose 4LO if you are driving off-road in
deep sand, deep mud, deep snow and climbing
or descending steep hills.
You can shift from 2-Wheel High (2HI) to 4-Wheel High
(4HI) or from 4-Wheel High (4HI) to 2-Wheel High
(2HI) while the vehicle is moving. Your front axle will
engage faster if you take your foot off of the accelerator
for a couple of seconds after you shift. In extremely
cold weather, it may be necessary to stop or slow the
vehicle to shift into 4-Wheel High (4HI).
When Using the Manual Transfer Case
·
All shifts should be made using quick motions. Slow
shifts may make it harder to shift.
·You may notice that it is harder to shift when the
vehicle is cold. When the vehicle warms up the
shifting will return to normal.
·While in 4-Wheel (4HI) or 4-Wheel Lo (4LO) you
may experience reduced fuel economy.
·Avoid driving in 4-Wheel Drive on clean, dry
pavement. It may cause your tires to wear faster, and
make your transfer case harder to shift and run
noisier.
Shifting from 2HI to 4HI
·
Shifts between 2HI and 4HI can be made at any
vehicle speed.
·It is easiest to shift the transfer case when
maintaining a constant speed or a slight
acceleration. If possible, avoid shifting while slowing
down, as it will may make it harder to shift.
·Shift your transfer case lever in one continuous
motion into either the 4HI or 2HI position.
·In extremely cold weather, it may be necessary to
slow or stop the vehicle to shift into 4HI until your
vehicle has warmed up.
·While in 4HI, your vehicle can be driven at any
posted legal speed limit.
2-38

Recommended Transfer Case Settings
Transfer Case Settings
Driving
Conditions2HIAUTO
4WD4HI 4LO N
Normal YES
Variable YES
Severe YES
Extreme YES
Vehicle in
Tow*YES
*See ªRecreational Vehicle Towingº in the Index for
further information.
You can choose among four driving settings:
h(2HI):This setting is used for driving in most street
and highway situations. Your front axle is not engaged
in two- wheel drive. This setting also provides the
best fuel economy.AUTO 4WD:This setting is ideal for use when road
conditions are variable. When driving your vehicle
in AUTO 4WD, the front axle is engaged, but the
vehicle's power is sent to the rear wheels. When the
vehicle senses a loss of traction, the system will
automatically engage four-wheel drive. Driving in this
mode results in slightly lower fuel economy than 2HI.
G(4HI):Use 4HI when you need extra traction, such
a on snowy or icy roads or in most off-road situations.
This setting also engages your front axle to help
drive your vehicle. This is the best setting to use when
plowing snow.
g(4LO):This setting also engages your front axle
and delivers extra torque. You may never need 4LO. It
sends maximum power to all four wheels. You might
choose 4LO if you are driving off-road in deep
sand, deep mud, deep snow and climbing or descending
steep hills.
2-40

{CAUTION:
Shifting the transfer case to NEUTRAL can
cause your vehicle to roll even if the
transmission is in PARK (P). You or someone
else could be seriously injured. Be sure to set
the parking brake before placing the transfer
case in NEUTRAL. See
Parking Brake on
page 2-48
.
NEUTRAL:Shift the vehicle's transfer case to
NEUTRAL only when towing your vehicle. See
Recreational Vehicle Towing on page 4-54orTowing
Your Vehicle on page 4-53for more information.Indicator lights in the switches show which setting your
transfer case is in. The indicator lights will come on
brie¯y when you turn on the ignition and one will stay on.
If the lights do not come on, you should take your
vehicle to your dealer for service. An indicator light will
¯ash while the transfer case is being shifted. It will
remain illuminated when the shift is complete. If
for some reason the transfer case cannot make a
requested shift, it will return to the last chosen setting.
If the SERVICE 4WD light stays on, you should take
your vehicle to your dealer for service. See
Service on
page 5-3for further information.
Shifting into 4HI or AUTO 4WD
Press and release the 4HI or AUTO 4WD switch. This
can be done at any speed (except when shifting
from 4LO), and the indicator light will ¯ash while shifting.
It will remain illuminated when the shift is completed.
Shifting into 2HI
Press and release the 2HI switch. This can be done at
any speed (except when shifting from 4LO).
2-41