2006 GMC SIERRA manual transmission

Range Selection Mode
(Allison Transmission®)
If your truck has an Allison Transmission®your vehicle
is equipped with a Range Selection System.
To use this feature, do the following:
1. Move the shift lever to the MANUAL MODE (M).
When in the MANUAL MODE, the transmission’s
current gear range will be the highest attainable
range with all the lower gears available.
2. Press the plus/minus buttons to upshift or downshift
selecting the desired range of gears for your current
driving conditions.The Range Selection Mode allows you to control the
vehicle’s engine and vehicle speed while driving
down hill by allowing you to select a desired gear.
The DIC shows the six available ranges with the
highest attainable range shown in brackets. See
Driver Information Center (DIC) on page 3-52and
DIC Operation and Displays on page 3-53for more
information.
While using the Range Selection mode feature, cruise
control and the Tow/Haul mode can be used.
Low Traction Mode
(Allison Transmission®)
If your vehicle has the DURAMAX®diesel engine and the
Allison Transmission®, it is equipped with a Low Traction
Mode that assists in vehicle acceleration when road
conditions are slippery, such as ice or snow. While at a
stop, selecting the second gear range using the Range
Selection system, will allow the Allison Transmission
®
to limit torque to the wheels after it detects wheel slip,
preventing the tires from spinning.
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.
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SeeTow/Haul Mode Light on page 3-50for more
information.
If your vehicle is equipped with the Performance
Package-Enhanced Towing, activating the manual
selectable ride will adjust the shock absorber
characteristics to enhance the ride and handling of the
vehicle for towing or hauling heavy loads.
Also see Tow Haul Mode underTowing a Trailer on
page 4-67for more information.
Tow/Haul Mode
(Allison Transmission®)
If your vehicle has an Allison Transmission®,itmay
have a Tow/Haul mode. 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 Turn 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 3-50for more
information.
Also see “Tow Haul Mode” underTowing a Trailer on
page 4-67for more information.
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Manual Transmission Operation
Five-Speed
(VORTEC™ 6.0L V8 Engine)
Here is 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 are going less
than 20 mph (32 km/h). If you have come to a complete
stop and it is 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.
FOURTH (4) and FIFTH (5):Shift into the higher
forward gears the same way you do for THIRD (3).
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.
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Six-Speed (VORTEC™ 8.1L V8 and
DURAMAX®™ 6.6L V8 Engines)
Here is 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.
During the rst 500 miles (805 km) of vehicle use,
start the vehicle moving in FIRST (1) gear. This allows
the clutch components to wear-in properly.FIRST (1):With the vehicle at a stop, release the brake,
press the clutch pedal and shift into FIRST (1). Then,
slowly let up on the clutch pedal as you press the
accelerator pedal. Only downshift into FIRST (1) when
the vehicle has come to a complete stop. If the shift lever
will not go into FIRST (1), put the lever in NEUTRAL and
let up on the clutch pedal to fully engage the clutch. Press
the clutch pedal again. Then, shift into FIRST (1).
SECOND (2):With the vehicle at a stop, release the
brake, press the clutch pedal and shift into SECOND (2).
Then, slowly let up on the clutch pedal as you press the
accelerator pedal. With the vehicle moving, press the
clutch pedal and upshift into SECOND (2) from FIRST (1)
while applying light pressure to the right on the shifter.
Then, slowly let up on the clutch pedal as you press the
accelerator pedal. If you come to a complete stop and the
shift lever will not go into SECOND (2), put the lever in
NEUTRAL and let up on the clutch pedal to fully engage
the clutch. Press the clutch pedal again. Then, shift into
SECOND (2).
THIRD (3):Press the clutch pedal and upshift into
THIRD (3). Then, slowly let up on the clutch pedal
as you press the accelerator pedal.
FOURTH (4), FIFTH (5) and SIXTH (6):Upshift
into the higher forward gears the same way as you
do THIRD (3). Slowly let up on the clutch pedal as
you press the accelerator pedal.
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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 Four-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.
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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An indicator light near the lever shows you the transfer
case settings:
Notice:Driving on clean, dry pavement in
four-wheel drive for an extended period of time may
cause premature wear on your vehicle’s powertrain.
Do not drive on clean, dry pavement in four-wheel
drive for extended periods of time.
4L (Four-Wheel Low):This setting also engages your
front axle and delivers extra torque. You may never need
4L. It sends maximum power to all four wheels. You might
choose 4L 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
high. The transmission gear shift feel will be exaggerated.
{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. SeeParking
Brake on page 2-52.N (Neutral):Shift to this setting only when your vehicle
needs to be towed. SeeRecreational Vehicle Towing
on page 4-62orTowing Your Vehicle on page 4-62.
2H (Two-Wheel High):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.
4H (Four-Wheel High):Use this setting 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.
You can shift from 2H to 4H or 4H high to 2H 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 four-wheel high.
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When Using the Manual Transfer Case

Shifting should be made using quick motions.
Shifting slowly may make it more difficult to shift.
You may notice that it is harder to shift when the
vehicle is cold. After the vehicle warms up the
shifting will return to normal.
While in 4H or 4L you may experience reduced fuel
economy.
Avoid driving in four-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 2H (Two-Wheel High) to
4H (Four-Wheel High)

Shifts between 2H and 4H 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 4H or 2H position.
In extremely cold weather, it may be necessary to
slow or stop the vehicle to shift into four-wheel high
until your vehicle has warmed up.
While in 4H, your vehicle can be driven at any posted
legal speed limit.
Shifting In or Out of 4L (Four-Wheel Low)
Notice:Shifting the transfer case into 4L 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 4L while the vehicle is moving faster than
3 mph (5 km/h).
Shifts into 4L 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 4L position.
When in 4L 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 position.
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7. If the engine is running, shift the transmission to
REVERSE (R) for one second, then shift the
transmission to DRIVE (D) for one second, or
FIRST (1) for vehicles equipped with a manual
transmission.
8. Turn the engine off, by turning the key to
ACCESSORY.
9. Place the transmission shift lever in PARK (P).
10. Turn the ignition to LOCK.
Shifting Out of NEUTRAL
To shift out of NEUTRAL:
1. Set the parking brake and apply the regular brake
pedal.
2. Turn the ignition to RUN with the engine off.
3. Shift the transmission to NEUTRAL (N).
4. Press the button for the desired transfer case
shift position (Two-Wheel High, Four-Wheel
High, AUTO 4WD, or Four-Wheel Low).
5. After the transfer case has shifted out of NEUTRAL
the red light will go out.
6. Release the parking brake.
7. You may start the engine and shift the transmission
to the desired position.Excessively shifting the transfer case into or out of the
different modes may cause the transfer case to enter the
shift protection mode. This will protect the transfer case
from possible damage and will only allow the transfer
case to respond to one shift per 10 seconds. The transfer
case may stay in this mode for up to three minutes.
Electronic Transfer Case
If your four-wheel-drive
vehicle has the electronic
transfer case, the transfer
case switches are located
to the left of the instrument
panel cluster.
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