2006 GMC SIERRA 4WD

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.
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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.
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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.
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Shifting into Four-Wheel High or AUTO
4WD (Automatic Four-Wheel Drive)
Press and release the four-wheel high or AUTO 4WD
switch. This can be done at any speed, except when
shifting from Four-Wheel Low, and the indicator light
will ash while shifting. It will remain on when the shift is
completed.
Shifting into Two-Wheel High
Press and release the Two-Wheel High switch.
This can be done at any speed, except when shifting
from Four-Wheel Low.
Shifting into Four-Wheel Low
Notice:Shifting the transfer case into
Four-Wheel Low 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 Four-Wheel Low while the vehicle is moving
faster than 3 mph (5 km/h).To shift to Four-Wheel Low, the ignition must be in RUN
and the vehicle must be stopped or moving less than
3 mph (5 km/h) with the transmission in NEUTRAL (N).
The preferred method for shifting into Four-Wheel Low is
to have your vehicle moving 1 to 2 mph (1.6 to 3.2 km/h).
Press and release the Four-Wheel Low switch. You must
wait for the Four-Wheel Low indicator light to stop
ashing and remain on before shifting your transmission
in gear.
Notice:Shifting the transmission into gear before
the Four-Wheel Low indicator light has stopped
ashing could damage the transfer case. To help
avoid damaging your vehicle, always wait for the
Four-Wheel Low indicator light to stop ashing
before shifting the transmission into gear.
It is typical for your vehicle to exhibit signicant
engagement noise and bump when shifting between
Four-Wheel Low and Four-Wheel High ranges or from
NEUTRAL (N) with the engine running.
If the Four-Wheel Low switch is pressed when your
vehicle is in gear and/or moving, the Four-Wheel Low
indicator light will ash for 30 seconds and not complete
the shift unless your vehicle is moving less than
3 mph (5 km/h) and the transmission is in NEUTRAL (N).
After 30 seconds the transfer case will shift to four-wheel
high mode.
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Shifting Out of Four-Wheel Low
To shift from Four-Wheel Low to Four-Wheel High,
AUTO 4WD, or Two-Wheel High, your vehicle must be
stopped or moving less than 3 mph (5 km/h) with the
transmission in NEUTRAL (N) and the ignition in RUN.
The preferred method for shifting out of Four-Wheel
Low is to have your vehicle moving 1 to 2 mph (1.6 to
3.2 km/h). Press and release the Four-Wheel High,
AUTO 4WD, or Two-Wheel High switch. You must wait
for the Four-Wheel High, AUTO 4WD, or Two-Wheel
High indicator light to stop ashing and remain on before
shifting your transmission into gear.
Notice:Shifting the transmission into gear before
the Four-Wheel Low indicator light has stopped
ashing could damage the transfer case. To help
avoid damaging your vehicle, always wait for the
Four-Wheel Low indicator light to stop ashing
before shifting the transmission into gear.
The transfer case may make noise and the vehicle
may jerk when the transfer case is shifted between
Four-Wheel Low and Four-Wheel High ranges or
from NEUTRAL with the engine running.
If the four-wheel high, AUTO 4WD, or Two-Wheel High
switch is pressed when your vehicle is in gear and/or
moving, the Four-Wheel High, AUTO 4WD, or
Two-Wheel High indicator light will ash for 30 seconds
but will not complete the shift unless your vehicle is
moving less than 3 mph (5 km/h) and the transmission
is in NEUTRAL (N).
Shifting Into NEUTRAL
{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.
To shift the transfer case to NEUTRAL do the following:
1. Make sure the vehicle is parked so that it will not roll.
2. Set the parking brake.
3. Start the vehicle or turn the ignition to RUN.
4. Put the transmission in NEUTRAL (N).
5. Shift the transfer case to Two-Wheel High.
6. Simultaneously press and hold the Two-Wheel High
and Four-Wheel Low buttons for 10 seconds. The
red NEUTRAL light will come on when the transfer
case shift to NEUTRAL is complete.
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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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SERVICE 4WD (Four-Wheel-Drive)
If a problem occurs with the four-wheel-drive system,
this message will appear on the DIC. If this message
appears, stop as soon as possible and turn off the
vehicle. Restart the vehicle and check for the message
on the DIC display. If the message is still displayed
or appears again when you begin driving, the
four-wheel-drive system needs service. See your
GM dealer.
SERVICE AIRBAG
If there is a problem with the airbag system, this message
will be displayed on the DIC. Have your GM dealer
inspect the system for problems. SeeAirbag Readiness
Light on page 3-35andAirbag System on page 1-70for
more information. Pressing any of the four DIC buttons
will acknowledge the message and clear it from the
DIC display. If your vehicle does not have the four DIC
buttons, pressing the trip odometer reset stem will
acknowledge the message and clear it from the
DIC display.
SERVICE BRAKE BOOSTER
{CAUTION:
Your brake system may not be working
properly if the SERVICE BRAKE BOOSTER
message is displayed.
If the brake system warning light is also on,
you should have the vehicle towed for service.
SeeBrake System Warning Light on page 3-41.
If the brake system warning light is not on, you
still have brakes, but the supplemental brake
assist system on vehicles with rear disc brakes
may not operate properly. In the event of a
vacuum loss, you may not have vacuum power
assist for braking. The brake pedal will be
harder to push and it will take longer to stop.
If you continue to drive with this message
displayed it can lead to a crash. Have the
brake system serviced as soon as possible.
If your vehicle has vacuum assist power brakes, this
message will be displayed on the DIC when there is a
problem with the Supplemental Brake Assist system.
3-61

Vehicle* Axle Ratio Maximum Trailer Weight GCWR
C-1500 Extended Cab Long Box (2WD)*
4800 V8 (Auto)3.23
3.735,800 lbs (2 631 kg)
6,800 lbs (3 084 kg)11,000 lbs (4 994 kg)
12,000 lbs (5 448 kg)
4800 V8 (Manual)3.23
3.733,800 lbs (1 724 kg)
4,800 lbs (2 177 kg)9,000 lbs (4 086 kg)
10,000 lbs (4 540 kg)
5300 V83.42
3.736,800 lbs (3 084 kg)
7,800 lbs (3 538 kg)12,000 lbs (5 448 kg)
13,000 lbs (5 902 kg)
* Fifth-wheel or gooseneck kingpin weight 15 percent to 25 percent of trailer weight up to 1,500 lbs (680 kg) maximum.
Vehicle* Axle Ratio Maximum Trailer Weight GCWR
K-1500 Regular Cab Short Box (4WD)
4300 V6 (Auto) 3.73 5,100 lbs (2 313 kg) 10,000 lbs (4 540 kg)
4300 V6 (Manual) 3.73 4,100 lbs (1 860 kg) 9,000 lbs (4 086 kg)
4800 V8 (Auto)3.42
3.73
4.107,100 lbs (3 221 kg)
7,100 lbs (3 221 kg)
8,100 lbs (3 674 kg)12,000 lbs (5 448 kg)
12,000 lbs (5 448 kg)
13,000 lbs (5 902 kg)
4800 V8 (Manual)3.42
3.73
4.105,100 lbs (2 313 kg)
5,100 lbs (2 313 kg)
6,100 lbs (2 767 kg)10,000 lbs (4 540 kg)
10,000 lbs (4 540 kg)
11,000 lbs (4 994 kg)
5300 V83.42
3.73
4.108,100 lbs (3 674 kg)
8,000 lbs (3 674 kg)
9,100 lbs (4 128 kg)13,000 lbs (5 902 kg)
13,000 lbs (5 902 kg)
14,000 lbs (6 356 kg)
* Fifth-wheel or gooseneck kingpin weight 15 percent to 25 percent of trailer weight up to 1,500 lbs (680 kg) maximum.
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