2007 GMC SIERRA CLASSIC 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 424for
further information.
You can choose among ve 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.Indicator lights in the switches show the current
setting. The indicator lights will come on briey
when you turn on the ignition and the last chosen
setting 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 shifting.
Fast ashing means the conditions are not
being met to make the desired shift, typically the
vehicle is going too fast, the automatic
transmission is not in NEUTRAL, or the clutch
pedal is not fully pressed. Slow ashing means the
shift is in progress. It will stay on when the shift
is completed. If for some reason the transfer case
cannot make a requested shift, it will return to
the last chosen setting.
AUTO 4WD (Automatic Four-Wheel Drive):This
setting is ideal for use when road surface
traction conditions are variable. When driving your
vehicle in AUTO 4WD, the front axle is engaged,
but the vehicle’s power is primarily sent to the rear
wheels. When the vehicle’s software determines
a need for more traction, the system will
transfer more power to the front wheels. Driving in
this mode results in slightly lower fuel economy
than Two-Wheel Drive High.
158

2m(Two-Wheel Drive 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 169.
N (NEUTRAL):Shift the vehicle’s transfer case to
N (NEUTRAL) only when towing your vehicle.
SeeRecreational Vehicle Towing on page 424or
Towing Your Vehicle on page 423for more
information.4
m(Four-Wheel Drive 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 the vehicle. This is the best setting to
use when plowing snow.
4
n(Four-Wheel Drive Low):This setting also
engages the front axle and delivers extra
torque. You may never need Four-Wheel Drive
Low. It sends maximum power to all four wheels.
You might choose Four-Wheel Drive 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 Drive
Low, the gear ratio provides additional torque
when compared to Four-Wheel Drive High. The
transmission gear shift feel will be exaggerated.
If the SERVICE 4WD message stays on the Driver
Information Center (DIC), you should take your
vehicle to your dealer for service. SeeDIC
Warnings and Messages on page 270for further
information.
159

Shifting into Four-Wheel Drive High or
AUTO 4WD (Automatic Four-Wheel Drive)
Press and release the Four-Wheel Drive High
or AUTO 4WD switch. This can be done at any
speed, except when shifting from Four-Wheel
Drive Low. The indicator light will ash while
shifting. It will remain on when the shift is
completed.
Shifting into Two-Wheel Drive High
Press and release the Two-Wheel Drive High
switch. This can be done at any speed, except
when shifting from Four-Wheel Drive Low.
See shifting out of Four-Wheel Drive Low later in
this section for more information.
Shifting into Four-Wheel Drive Low
Notice:Shifting the transfer case into
Four-Wheel Drive 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 Drive
Low while the vehicle is moving faster
than 3 mph (5 km/h).To shift to Four-Wheel Drive 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 Drive Low
is to have your vehicle moving 1 to 2 mph
(1.6 to 3.2 km/h). Press and release the
Four-Wheel Drive Low switch. You must wait for
the Four-Wheel Drive Low indicator light to
stop ashing and remain on before shifting the
transmission into gear.
Notice:Shifting the transmission into gear
before the Four-Wheel Drive Low indicator light
has stopped ashing could damage the
transfer case. To help avoid damaging your
vehicle, always wait for the Four-Wheel
Drive 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 Drive Low and Four-Wheel
Drive High ranges or from NEUTRAL (N) with
the engine running.
160

If the Four-Wheel Drive Low switch is pressed
when your vehicle is in gear and/or moving,
the Four-Wheel Drive Low indicator light will ash
for 30 seconds and the vehicle will not complete
the shift unless it 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 Drive High mode.
Shifting Out of Four-Wheel Drive Low
To shift from Four-Wheel Drive Low to Four-Wheel
Drive High, AUTO 4WD, or Two-Wheel Drive
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
Drive Low is to have your vehicle moving 1 to
2 mph (1.6 to 3.2 km/h). Press and release the
Four-Wheel Drive High, AUTO 4WD, or
Two-Wheel Drive High switch. You must wait for
the Four-Wheel Drive High, AUTO 4WD, or
Two-Wheel Drive High indicator light to stop
ashing and stay on before shifting the
transmission into gear.Notice:Shifting the transmission into gear
before the Four-Wheel Drive Low indicator light
has stopped ashing could damage the
transfer case. To help avoid damaging your
vehicle, always wait for the Four-Wheel
Drive 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 Drive Low and Four-Wheel
Drive High ranges or from NEUTRAL with the
engine running.
If the Four-Wheel Drive high, AUTO 4WD, or
Two-Wheel Drive High switch is pressed when
your vehicle is in gear and/or moving, the
Four-Wheel Drive High, AUTO 4WD, or
Two-Wheel Drive High indicator light will ash for
30 seconds but the vehicle will not complete
the shift unless it is moving less than 3 mph
(5 km/h) and the transmission is in NEUTRAL (N).
161

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 169.
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 and apply the regular
brake pedal.
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
Drive High.
6. Simultaneously press and hold the Two-Wheel
Drive High and Four-Wheel Drive Low buttons
for 10 seconds. The red NEUTRAL light will
come on when the transfer case shift to
NEUTRAL is complete.
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 that have a manual
transmission.
8. Turn the engine off, by turning the key to
ACCESSORY.
9. Place the transmission shift lever in
PARK (P).
10. Release the parking brake prior to moving the
vehicle.
11. Turn the ignition to LOCK.
162

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 Drive High,
Four-Wheel Drive High, AUTO 4WD, or
Four-Wheel Drive Low).5. After the transfer case has shifted out of
NEUTRAL the red light will go out.
6. Release the parking brake prior to moving the
vehicle.
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 mode
protects the transfer case from possible damage
and only allows the transfer case to respond
to one shift per 10 seconds. The transfer case may
stay in this mode for up to three minutes.
163

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.
Recommended Transfer Case Settings
Driving ConditionsTransfer Case Settings
2m4m4nN
Normal YES
Severe YES
Extreme YES
Vehicle in Tow* YES
*SeeRecreational Vehicle Towing on page 424or
Towing Your Vehicle on page 423for further
information.
Use these switches to shift into and out of
four-wheel drive. You can choose among
three driving settings:
Indicator lights in the switches show you which
setting you are in. The indicator lights will come on
briey when you turn on the ignition and the last
chosen setting will stay on. If the lights do not
come on, you should take your vehicle in to your
dealer for service. An indicator light will ash
while shifting. Fast ashing means the conditions
are not being met to make the desired shift,
typically the vehicle is going too fast, the automatic
transmission is not in neutral, or the clutch
pedal is not fully pressed. Slow ashing means
the shift is in progress. It will stay on when the shift
is completed. If for some reason the transfer
case cannot make a requested shift, it will return
to the last chosen setting.
2
m(Two-Wheel Drive High):This setting is for
driving in most street and highway situations.
The front axle is not engaged in two-wheel drive.
164

{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 169.
(N) NEUTRAL:Shift the vehicle’s transfer case to
NEUTRAL only when towing your vehicle. See
Recreational Vehicle Towing on page 424or
Towing Your Vehicle on page 423for more
information.
4
m(Four-Wheel Drive High):This setting
engages the front axle to help drive your vehicle.
Use Four-Wheel Drive High when you need
extra traction, such as on snowy or icy roads, or in
most off-road situations.4
n(Four-Wheel Drive Low):This setting also
engages your front axle to give you extra
traction. You may never need Four-Wheel Drive
Low. It sends the maximum power to all four
wheels. You might choose Four-Wheel Drive Low
if you were driving off-road in sand, mud or
deep snow and while climbing or descending steep
hills. When operating in Four-Wheel Drive Low,
the gear ratio provides additional torque when
compared to Four-Wheel Drive High. The
transmission gear shift feel will be exaggerated.
Shifting from Two-Wheel Drive High
to Four-Wheel Drive High
Press and release the Four-Wheel Drive High
switch. This can be done at any speed. The front
axle will lock automatically with some delay.
Shifting from Four-Wheel Drive High to
Two-Wheel Drive High
Press and release the Two-Wheel Drive High
switch. This can be done at any speed. The front
axle will unlock automatically with some delay.
165