2004 GMC SIERRA Owner's Manual

Up-Shift Light
If you have a manual
transmission, you may
have a shift light. This light
will show you when to
shift to the next higher gear
for best fuel economy.
When this light comes on, you can shift to the next
higher gear if weather, road and traffic conditions allow.
For the best fuel economy, accelerate slowly and
shift when the light comes on.
While you accelerate, it is normal for the light to go on
and off if you quickly change the position of the
accelerator.
If your vehicle has four-wheel drive and is equipped with
a manual transmission, disregard the SHIFT light
when the transfer case is in 4-Wheel Low.
Ignore the SHIFT light when you downshift.
Four-Wheel Drive
If your vehicle has four-wheel drive, you can send your
engine's driving power to all four wheels for extra traction.
To get the most satisfaction out of four-wheel drive, you
must be familiar with its operation. Read the part that
follows before using four-wheel drive. See the
appropriate text for the transfer case in your vehicle.
Notice:Driving on pavement in four-wheel drive for
an extended period of time may cause premature
wear on your vehicle's powertrain. Do not drive
in four-wheel drive on pavement for extended
periods of time.
Front Axle Locking Feature
The front axle locks and unlocks automatically when
you shift the transfer case. Some delay for the axle to
lock or unlock is normal.
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Manual Transfer Case
The transfer case shift lever is on the ¯oor to the right
of the driver. Use this lever to shift into and out of
four-wheel drive.An 4WD indicator light will
illuminate when you shift
into four-wheel drive
and the front axle engages.
Some delay between shifting and the indicator's lighting
is normal.
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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.
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Shifting In or Out of 4LO
Notice:Shifting the transfer case into 4LO while
moving at speeds faster than 3 mph (5 km/h)
may cause premature wear to the transfer case, and
may cause the gears to grind. To avoid causing
premature wear, and grinding the gears, do not shift
the transfer case into 4LO while the vehicle is
moving faster than 3 mph (5 km/h).
Shifts into 4LO can be made with the vehicle at a stop,
or while slowly rolling about 1 to 3 mph (2 to 5 km/h).
·Shift the automatic transmission into NEUTRAL
(N), or with a manual transmission, press the
clutch pedal, or shift into NEUTRAL (N).
·Shift the transfer case shift lever in one continuous
motion into the 4LO position.
·When in 4LO do not drive faster than 45 mph.
This will reduce wear and extend the life of
your transfer case.
Shifting In or Out of NEUTRAL
1. With the vehicle running and the engine at an idle
set the parking brake.
2. Place the transmission into NEUTRAL (N).
Shift the transfer case in one continuous motion into or
out of the NEUTRAL (N) position.
Automatic Transfer Case
The transfer case buttons
are located to the left of
the instrument panel
cluster.
Use these switches to shift into and out of four-wheel
drive.
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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).
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Shifting into 4LO
To shift to 4LO, the ignition must be in RUN and the
vehicle must be stopped or moving less than 3 mph
(4.8 km/h) with the transmission in NEUTRAL (N). The
preferred method for shifting into 4LO is to have
your vehicle moving 1 to 2 mph (1.6 to 3.2 km/h). Press
and release the 4LO switch. You must wait for the
4LO indicator light to stop ¯ashing and remain
illuminated before shifting your transmission in gear.
Notice:Shifting the transmission into gear before
the 4LO indicator light has stopped ¯ashing
could damage the transfer case. To help avoid
damaging your vehicle, always wait for the
4LO indicator light to stop ¯ashing before shifting
the transmission into gear.
It is typical for your vehicle to exhibit signi®cant
engagement noise and bump when shifting between
4LO and 4HI ranges or from NEUTRAL with the engine
running.
If the 4LO switch is pressed when your vehicle is in
gear and/or moving, the 4LO indicator light will ¯ash for
30 seconds and not complete the shift unless your
vehicle is moving less than 3 mph (4.8 km/h) and the
transmission is in NEUTRAL (N). After 30 seconds
the transfer case will shift to 4HI mode.
Shifting Out of 4LO
To shift from 4LO to 4HI, AUTO 4WD or 2HI your vehicle
must be stopped or moving less than 3 mph (4.8 km/h)
with the transmission in NEUTRAL (N) and the ignition in
RUN. The preferred method for shifting out of 4LO is to
have your vehicle moving 1 to 2 mph
(1.6 to 3.2 km/h). Press and release the 4HI, AUTO 4WD
or 2HI switch. You must wait for the 4HI, AUTO 4WD or
2HI indicator light to stop ¯ashing and remain illuminated
before shifting your transmission into gear.
Notice:Shifting the transmission into gear before
the 4LO indicator light has stopped ¯ashing
could damage the transfer case. To help avoid
damaging your vehicle, always wait for the
4LO indicator light to stop ¯ashing before shifting
the transmission into gear.
It is typical for your vehicle to exhibit signi®cant
engagement noise and bump when shifting between
4LO and 4HI ranges or from NEUTRAL with the engine
running.
If the 4HI, AUTO 4WD or 2HI switch is pressed when
your vehicle is in gear and/or moving, the 4HI,
AUTO 4WD or 2HI indicator light will ¯ash for
30 seconds but will not complete the shift unless your
vehicle is moving less than 3 mph (4.8 km/h) and
the transmission is in NEUTRAL (N).
2-42