2006 GMC SIERRA 1500 tow

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.
2-34

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.
2-36

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.A 4WD indicator light
comes on when you shift
into four-wheel drive and
the front axle engages. See
Four-Wheel-Drive Light on
page 3-50.
Some delay between shifting and when the indicator
light comes on is normal.
Recommended Transfer Case Settings
Driving ConditionsTransfer Case Settings
2H 4H 4L N
Normal YES
Severe YES
Extreme YES
Vehicle in Tow* YES
*SeeRecreational Vehicle Towing on page 4-62
orTowing Your Vehicle on page 4-62for further
information.
2-39

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.
2-40

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.
Recommended Transfer Case Settings
Driving
ConditionsTransfer Case Settings
2
mAUTO
4WD4m4nN
Normal YES
Variable YES
Severe YES
Extreme YES
Vehicle in
Tow*YES
*SeeRecreational Vehicle Towing on page 4-62for
further information.
You can choose among four driving settings:
Notice:Driving on clean, dry pavement in
Four-Wheel-Drive High or Four-Wheel-Drive Low 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 High or
Four-Wheel-Drive Low for extended periods of time.
AUTO 4WD (Automatic Four-Wheel Drive):This
setting is ideal for use when road surface traction
conditions are variable. When driving your vehicle in
Automatic Four-Wheel Drive, the front axle is engaged,
but the vehicle’s power is sent to the rear wheels.
2-42

When the vehicle detects a loss of traction, the system
will automatically engage four-wheel drive. Driving in
this mode results in slightly lower fuel economy than
Two-Wheel High.
2
m(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.
{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. SeeParking Brake on
page 2-52.
N (NEUTRAL):Shift the vehicle’s transfer case to
N (NEUTRAL) only when towing your vehicle. See
Recreational Vehicle Towing on page 4-62orTowing
Your Vehicle on page 4-62for more information.4
m(Four-Wheel High):Use this setting 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.
4
n(Four-Wheel Low):This setting also engages
your front axle and delivers extra torque. You may never
need Four-Wheel Low. It sends maximum power to all
four wheels. You might choose Four-Wheel Low 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.
Indicator lights in the switches show which setting your
transfer case is in. The indicator lights will come on briey
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 stay on 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 message stays on, you should take
your vehicle to your dealer for service. SeeDIC Warnings
and Messages on page 3-55for further information.
2-43

Recommended Transfer Case Settings
Driving ConditionsTransfer Case Settings
2m4m4nN
Normal YES
Severe YES
Extreme YES
Vehicle in Tow* YES
*SeeRecreational Vehicle Towing on page 4-62or
Towing Your Vehicle on page 4-62for further
information.
Use these switches to shift into and out of four-wheel
drive. You can choose among three driving settings:
2
m(Two-Wheel High):This setting is for driving in
most street and highway situations. Your front axle is not
engaged in two-wheel drive.
{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. SeeParking Brake on
page 2-52.
(N) NEUTRAL:Shift the vehicle’s transfer case to
NEUTRAL only when towing your vehicle. See
Recreational Vehicle Towing on page 4-62orTowing
Your Vehicle on page 4-62for more information.
4
m(Four-Wheel High):This setting engages your
front axle to help drive your vehicle. Use four-wheel high
when you need extra traction, such as on snowy or icy
roads, or in most off-road situations.
2-47

Parking Brake
To set the parking brake, hold the regular brake pedal
down with your right foot. Push down the parking brake
pedal with your left foot.
A chime will activate and the warning light will ash when
the parking brake is applied and the vehicle is moving at
least 3 mph (5 km/h) for at least three seconds.
To release the parking brake, hold the regular brake
pedal down. Pull the bottom edge of the lever, located
above the parking brake pedal, with the parking brake
symbol, to release the parking brake.If the ignition is on when the parking brake is released,
the brake system warning light will go off.
Notice:Driving with the parking brake on can
overheat the brake system and cause premature
wear or damage to brake system parts. Verify that
the parking brake is fully released and the brake
warning light is off before driving.
If you are towing a trailer and are parking on any hill,
seeTowing a Trailer on page 4-67.
2-52