2004 GMC SIERRA DENALI engine

Automatic Transmission Operation
Your vehicle is equipped with an automatic transmission
that features an electronic shift position indicator
located within the instrument panel cluster. This display
is powered anytime the shift lever is capable of being
moved out of PARK (P). See
Fuses and Circuit Breakers
on page 5-105.
There are several different positions for your shift lever.
PARK (P):This position locks your wheels. It's the
best position to use when you start your engine because
your vehicle can't move easily.
{CAUTION:
It is 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.
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.
CAUTION: (Continued)
CAUTION: (Continued)
To be sure your vehicle will not move, even
when you are on fairly level ground, always set
your parking brake and move the shift lever to
PARK (P). See
Shifting Into Park (P) on
page 2-26
. If you are pulling a trailer, see
Towing a Trailer on page 4-58.
REVERSE (R):Use this gear to back up.
Notice:Shifting to REVERSE (R) while your vehicle
is moving forward could damage the transmission.
The repairs would not be covered by your warranty.
Shift to REVERSE (R) only after your vehicle is
stopped.
To rock your vehicle back and forth to get out of snow,
ice or sand without damaging your transmission,
see If You Are Stuck: In Sand, Mud, Ice or Snow on
page 4-46.
2-22

NEUTRAL (N):In this position, your engine doesn't
connect with the wheels. To restart when you're already
moving, use NEUTRAL (N) only. Also, use
NEUTRAL (N) when your vehicle is being towed.
{CAUTION:
Shifting into a drive gear while your engine is
running at high speed is dangerous. Unless
your foot is ®rmly on the brake pedal, your
vehicle could move very rapidly. You could
lose control and hit people or objects. Do not
shift into a drive gear while your engine is
running at high speed.
Notice:Shifting out of PARK (P) or NEUTRAL (N)
with the engine running at high speed may damage
the transmission. The repairs would not be
covered by your warranty. Be sure the engine is not
running at high speed when shifting your vehicle.DRIVE (D):This position is for normal driving. If you
need more power for passing, and you're:
·Going less than about 35 mph (55 km/h), push your
accelerator pedal about halfway down.
·Going about 35 mph (55 km/h) or more, push the
accelerator all the way down.
You'll shift down to the next gear and have more power.
DRIVE (D) can be used when towing a trailer, carrying
a heavy load, driving on steep hills or for off-road driving.
You may want to shift the transmission to THIRD (3)
or, if necessary, a lower gear selection if the
transmission shifts too often.
THIRD (3):This position is also used for normal driving,
however it offers more power and lower fuel economy
than DRIVE (D).
SECOND (2):This position gives you more power but
lower fuel economy. You can use SECOND (2) on
hills. It can help control your speed as you go down
steep mountain roads, but then you would also want to
use your brakes occasionally.
If you manually select SECOND (2), the transmission
will drive in second gear. You may use this feature
for reducing the speed of the rear wheels when you are
trying to start your vehicle from a stop on slippery
road surfaces.
2-23

FIRST (1):This position gives you even more power
(but lower fuel economy) than SECOND (2). You
can use it on very steep hills, or in deep snow or mud.
If the shift lever is put in FIRST (1) while the vehicle
is moving forward, the transmission won't shift into ®rst
gear until the vehicle is going slowly enough.
Notice:Spinning the tires or holding the vehicle in
one place on a hill using only the accelerator
pedal may damage the transmission. If you are
stuck, do not spin the tires. When stopping on a hill,
use the brakes to hold the vehicle in place.
On cold days, approximately 32ÉF (0ÉC) or colder, your
transmission is designed to shift differently until the
engine reaches normal operating temperature. This is
intended to improve heater performance.
Tow/Haul Mode
Your vehicle may be equipped with a Tow/Haul mode.
The switch is located on the end of the column shift
lever. You can use this feature to assist when towing or
hauling a heavy load.
2-24

When Tow/Haul is
activated the Tow/Haul
symbol will illuminate
on the instrument panel
cluster. See
Tow/Haul
ModeunderTowing
a Trailer on page 4-58for
more information.
All-Wheel Drive
With this feature, engine power is sent to all four wheels
all the time.
This is like four-wheel drive, but there is no separate
lever or switch to engage or disengage the front axle.
It is fully automatic, and adjusts itself as needed for road
conditions.
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,
see
Towing a Trailer on page 4-58.
2-25

Shifting Into Park (P)
{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 Ð not
in NEUTRAL. If you are pulling a trailer, see
Towing a Trailer on page 4-58.
1. Hold the brake pedal down with your right foot and
set the parking brake.2. Move the shift lever into PARK (P) like this:
·Pull the shift lever toward you.
2-26

·Move the lever up as far as it will go.
3. Turn the ignition key to LOCK.
4. 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).
Leaving Your Vehicle With the Engine
Running
{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.
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.
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
wasn't fully locked into PARK (P).
2-27

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.
Engine Exhaust
{CAUTION:
Engine exhaust can kill. It contains the gas
carbon monoxide (CO), which you can not 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
modi®ed 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.
2-29

Running Your Engine While You
Are 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 2-29.
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 Ð with CO Ð can come in easily.
NEVER park in a garage with the engine
running.
Another closed-in place can be a blizzard.
See
Winter Driving on page 4-42.
{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. 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
you are on fairly level ground, always set your
parking brake and move the shift lever to
PARK (P).
Follow the proper steps to be sure your vehicle will not
move. See
Shifting Into Park (P) on page 2-26.
If you are pulling a trailer, see
Towing a Trailer on
page 4-58.
2-30