2007 GMC SIERRA CLASSIC Owners Manual

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 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.
7. After the transfer case has shifted out of
NEUTRAL the red light will go out.
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 429.
169

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, see
Towing a Trailer on page 429.1. 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.
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).
170

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.
171

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).
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 140and “Torque Lock”
underShifting Out of Park (P) (Automatic
Transmission) on page 172.
If your vehicle has an Allison Transmission
®, the
transmission has 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
clunking noise when the selector lever is movedfrom 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
not 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.
172

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.
173

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.
CAUTION: (Continued)
CAUTION: (Continued)

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 has
been modied improperly.
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.
174

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
underEngine Exhaust on page 174.
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 402.
{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.
175

{CAUTION:
Four-wheel drive vehicles with the transfer
case in NEUTRAL will allow the vehicle to
roll, even if your automatic transmission
shift lever is in PARK (P). So, be sure the
transfer case is in a drive gear — not in
NEUTRAL. Always set your parking brake.
Follow the proper steps to be sure your vehicle
will not move. SeeShifting Into Park (P)
(Automatic Transmission) on page 170.
If you are pulling a trailer, seeTowing a Trailer on
page 429.
Mirrors
Manual Rearview Mirror
Pull or push the tab under the inside rearview
mirror to adjust it to the night or daytime setting. In
the nighttime setting, the glare from headlamps
behind the vehicle will be less intense.
Automatic Dimming Rearview Mirror
with OnStar
®, Compass and
Temperature Display
Your vehicle may have this feature. When on, an
automatic dimming mirror automatically dims
to the proper level to minimize glare from lights
behind you after dark.
The mirror also includes a dual display in the
upper right corner of the mirror face. The compass
reading and the outside temperature will both
appear in the display at the same time.
P(On/Off):This is the on/off button.
Temperature and Compass Display
Press the on/off button, located to the far
left, briey to turn the compass/temperature
display on or off.
If the display reads CAL, you will need to calibrate
the compass. For more information on calibration,
see below.
176