2007 GMC SIERRA CLASSIC automatic transmission

Shifting from Four-Wheel Drive Low to
Four-Wheel Drive High or Two-Wheel
Drive High
To shift from Four-Wheel Drive Low to Four-Wheel
Drive High 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) for an automatic transmission or
the clutch pedal pressed for a manual
transmission. The preferred method for shifting out
of Four-Wheel Drive Low is to have your vehicle
moving 3 mph (5 km/h).
Press and release the Two-Wheel Drive High or
Four-Wheel Drive High switch. You must wait
for the Two-Wheel Drive High or Four-Wheel Drive
High indicator light to stop ashing and stay on
before shifting the transmission into gear or
releasing the clutch pedal.
If the Four-Wheel Drive High switch is pressed
when your vehicle is in gear, the Four-Wheel Drive
High indicator light will ash for 30 seconds but
the vehicle will not complete the shift unless
it is moving slower 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 169.
To shift the transfer case to NEUTRAL, rst make
sure the vehicle is parked so that it will not roll:
1. Set the parking brake and apply the regular
brake pedal.
2. Start the vehicle or turn the ignition to RUN.
3. Press the foot brake pedal and put the
transmission in NEUTRAL (N).
4. Shift the transfer case to Two-Wheel
Drive High.
167

5. 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.
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
that have a manual transmission. 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 that have a manual transmission.
10. Release the parking brake prior to moving the
vehicle.
11. 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 that have 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 Drive High,
Four-Wheel Drive High, or Four-Wheel
Drive Low).
4. After the transfer case has shifted out of
NEUTRAL the red light will go out.
5. Release the parking brake prior to moving the
vehicle.
168

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

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

Instrument Panel Overview........................ 210
Hazard Warning Flashers.......................... 212
Other Warning Devices............................. 213
Horn.......................................................... 213
Tilt Wheel.................................................. 213
Turn Signal/Multifunction Lever.................. 214
Turn and Lane-Change Signals................. 214
Headlamp High/Low-Beam Changer.......... 215
Flash-to-Pass............................................ 216
Windshield Wipers..................................... 216
Windshield Washer.................................... 217
Cruise Control........................................... 217
Headlamps................................................ 221
Headlamps on Reminder........................... 222
Daytime Running Lamps (DRL)................. 222
Automatic Headlamp System..................... 223
Fog Lamps................................................ 225
Auxiliary Roof Mounted Lamp.................... 226
Instrument Panel Brightness...................... 226
Dome Lamps............................................. 226
Dome Lamp Override................................ 227
Entry Lighting............................................ 227
Exit Lighting.............................................. 227Front Reading Lamps................................ 227
Cargo Lamp.............................................. 228
Accessory Power Outlet(s)........................ 228
Ashtray(s) and Cigarette Lighter................ 229
Climate Controls......................................... 230
Climate Control System............................. 230
Dual Climate Control System..................... 231
Dual Automatic Climate Control System.... 235
Outlet Adjustment...................................... 243
Warning Lights, Gages, and Indicators..... 244
Instrument Panel Cluster........................... 245
Speedometer and Odometer...................... 246
Trip Odometer........................................... 246
Tachometer............................................... 246
Safety Belt Reminder Light........................ 247
Airbag Readiness Light............................. 247
Airbag Off Light......................................... 248
Passenger Airbag Status Indicator............. 250
Battery Warning Light................................ 253
Voltmeter Gage......................................... 253
Up-Shift Light (Manual Transmission)........ 254
Brake System Warning Light..................... 254
Section 3 Instrument Panel
207