2006 GMC SIERRA 1500 Owners Manual

4. Shift the transfer case to Two-Wheel High.
5. 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.
6. Start the engine if it is not already running.
7. Press and hold the foot brake pedal and Shift the
transmission to REVERSE (R) for one second, then
shift the transmission for one second to DRIVE (D)
for an automatic transmission, or FIRST (1) for
vehicles equipped with a manual transmission and
then let out the clutch. This is to ensure the transfer
case is in NEUTRAL. If not, repeat this procedure
starting at Step 3.
8. Turn the engine off, by turning the key to
ACCESSORY.
9. Place the transmission shift lever in PARK (P)
for an automatic transmission, or FIRST (1) for
vehicles equipped with a manual transmission.
10. Turn the ignition to LOCK.Shifting Out of NEUTRAL
To shift out of NEUTRAL:
1. Set the parking brake and press and hold the
regular brake pedal.
2. Shift the transmission to NEUTRAL (N) for an
automatic transmission, or press the clutch pedal
for vehicles equipped with a manual transmission.
Then turn the ignition to RUN with the engine off.
3. Press the button for the desired transfer case shift
position (Two-Wheel High, Four-Wheel High, or
Four-Wheel Low).
4. After the transfer case has shifted out of NEUTRAL
the red light will go out.
5. Release the parking brake.
6. 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.
7. After the transfer case has shifted out of NEUTRAL
the red light will go out.
2-51

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

Shifting Into Park (P)
(Automatic Transmission)
{CAUTION:
It can be dangerous to get out of your vehicle if
the shift lever is not fully in PARK (P) with the
parking brake rmly set. Your vehicle can roll.
If you have left the engine running, the vehicle
can move suddenly. You or others could be
injured. To be sure your vehicle will not move,
even when you are on fairly level ground, use
the steps that follow. With four-wheel drive, if
your transfer case is in NEUTRAL, your vehicle
will be free to roll, even if your shift lever is in
PARK (P). So, be sure the transfer case is in a
drive gear — not in NEUTRAL. If you are pulling
a trailer, seeTowing a Trailer on page 4-67.1. Hold the brake pedal down with your right foot and
set the parking brake.
2. Move the shift lever into the PARK (P) position by
pulling the shift lever toward you and moving it up
as far as it will go.
3. If your vehicle has four-wheel drive, be sure
the transfer case is in a drive gear – not in
NEUTRAL (N).
4. Turn the ignition key to LOCK.
5. Remove the key and take it with you. If you can
leave your vehicle with the ignition key in your
hand, your vehicle is in PARK (P).
2-53

Leaving Your Vehicle With the Engine
Running (Automatic Transmission)
{CAUTION:
It can be dangerous to leave your vehicle with
the engine running. Your vehicle could move
suddenly if the shift lever is not fully in
PARK (P) with the parking brake rmly set.
If you have four-wheel drive and your transfer
case is in NEUTRAL, your vehicle will be free to
roll, even if your shift lever is in PARK (P).
So be sure the transfer case is in a drive
gear — not in NEUTRAL.
And, if you leave the vehicle with the engine
running, it could overheat and even catch re.
You or others could be injured. Do not leave
your vehicle with the engine running unless
you have to.If you have to leave your vehicle with the engine running,
be sure your vehicle is in PARK (P) and the parking brake
is rmly set before you leave it. After you move the shift
lever into PARK (P), hold the regular brake pedal down.
Then, see if you can move the shift lever away from
PARK (P) without rst pulling it toward you. If you can,
it means that the shift lever was not fully locked into
PARK (P).
Torque Lock (Automatic Transmission)
If you are parking on a hill and you do not shift your
transmission into PARK (P) properly, the weight of the
vehicle may put too much force on the parking pawl in the
transmission. You may nd it difficult to pull the shift lever
out of PARK (P). This is called “torque lock.” To prevent
torque lock, set the parking brake and then shift into
PARK (P) properly before you leave the driver’s seat. To
nd out how, see “Shifting Into PARK (P)” listed earlier in
this section.
When you are ready to drive, move the shift lever out of
PARK (P) before you release the parking brake.
If torque lock does occur, you may need to have another
vehicle push yours a little uphill to take some of the
pressure from the parking pawl in the transmission,
so you can pull the shift lever out of PARK (P).
2-54

Shifting Out of Park (P)
(Automatic Transmission)
Your vehicle has an automatic transmission shift lock
control system which locks the shift lever in PARK (P)
when the ignition is in the LOCK position. You have to
fully apply your regular brakes before you can shift from
PARK (P) when the ignition is in RUN. SeeAutomatic
Transmission Operation on page 2-26and “Torque Lock”
underShifting Out of Park (P) (Automatic Transmission)
on page 2-55.
If your vehicle has an Allison Transmission
®, the
transmission is equipped with a park pawl designed to
hold the higher weight of commercial medium duty trucks.
Therefore, the Allison Transmission
®uses larger parts
than other automatic transmissions. These larger parts
may sometimes make a clunk noise when the selector
lever is moved from DRIVE (D) or REVERSE (R) to
PARK (P). This is normal and there is no damage
occurring during these shifts.If you cannot shift out of PARK (P), ease pressure on
the shift lever and push the shift lever all the way up into
PARK (P) as you maintain brake application. Then, move
the shift lever into the gear you want.
If you ever hold the brake pedal down but still can’t shift
out of PARK (P), try this:
1. Turn the key to ACCESSORY. There is no shift
interlock in this key position.
2. Apply and hold the brake until the end of Step 4.
3. Shift the transmission to NEUTRAL (N).
4. Start the vehicle and then shift to the gear you want.
5. Have the system xed as soon as you can.
2-55

Parking Your Vehicle
(Manual Transmission)
{CAUTION:
Shifting the transfer case to NEUTRAL can
cause your vehicle to roll even if the manual
transmission is in gear. Your 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
for more information.
Before you get out of your vehicle, move the shift lever
into REVERSE (R), and rmly apply the parking brake.
Once the shift lever has been placed into REVERSE (R)
with the clutch pedal pressed in, you can turn the ignition
key to LOCK, press the key release button, remove the
key and release the clutch.
If you are parking on a hill, or if you are pulling a trailer,
seeTowing a Trailer on page 4-67.
Parking Over Things That Burn
{CAUTION:
Things that can burn could touch hot exhaust
parts under your vehicle and ignite. Do not
park over papers, leaves, dry grass, or other
things that can burn.
2-56

Engine Exhaust
{CAUTION:
Engine exhaust can kill. It contains the gas
carbon monoxide (CO), which you cannot see or
smell. It can cause unconsciousness and death.
You might have exhaust coming in if:
Your exhaust system sounds strange or
different.
Your vehicle gets rusty underneath.
Your vehicle was damaged in a collision.
Your vehicle was damaged when driving
over high points on the road or over road
debris.
Repairs were not done correctly.
Your vehicle or exhaust system had been
modied improperly.
CAUTION: (Continued)
CAUTION: (Continued)
If you ever suspect exhaust is coming into
your vehicle:
Drive it only with all the windows down to
blow out any CO; and
Have your vehicle xed immediately.
2-57

Running the Engine While Parked
It is better not to park with the engine running. But if you
ever have to, here are some things to know.
{CAUTION:
Idling the engine with the climate control
system off could allow dangerous exhaust into
your vehicle. See the earlier caution under
Engine Exhaust on page 2-57.
Also, idling in a closed-in place can let deadly
carbon monoxide (CO) into your vehicle even if
the climate control fan is at the highest setting.
One place this can happen is a garage.
Exhaust — with CO — can come in easily.
NEVER park in a garage with the engine
running.
Another closed-in place can be a blizzard.
SeeWinter Driving on page 4-42.
{CAUTION:
It can be dangerous to get out of your vehicle
if the automatic transmission shift lever is not
fully in PARK (P) with the parking brake rmly
set. Your vehicle can roll. Do not leave your
vehicle when the engine is running unless you
have to. If you have left the engine running,
the vehicle can move suddenly. You or others
could be injured. To be sure your vehicle will
not move, even when it is on fairly level
ground, always set the parking brake and
move the automatic transmission shift lever
to PARK (P), or the manual transmission shift
lever to NEUTRAL.
2-58