GMC SIERRA 1999 Owners Manual

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2-13 Key Release Button (Manual Transmission)
The ignition key cannot be
removed from the ignition
of manual transmission
vehicles unless the key
release button is used.
To remove the key on manual transmission vehicles,
turn the key to OFF, then press the button and turn the
key to LOCK. Do not hold the button in while turning
the key to OFF. Keeping your finger on the button, pull
the key straight out.
On automatic transmission vehicles, turn the key to
LOCK and pull it straight out.
Starting Your Gasoline Engine
If you have a diesel engine, see ªStarting Your Diesel
Engineº in the Diesel Engine Supplement.
Automatic Transmission
Move your shift lever to PARK (P) or NEUTRAL (N).
Your engine won't start in any other position
-- that's a
safety feature. To restart when you're already moving,
use NEUTRAL (N) only.
NOTICE:
Don't try to shift to PARK (P) if your vehicle is
moving. If you do, you could damage the
transmission. Shift to PARK (P) only when
your vehicle is stopped.
Manual Transmission
The gear selector should be in NEUTRAL and the
parking brake engaged. Hold the clutch pedal to the floor
and start the engine. Your vehicle won't start if the clutch
pedal is not all the way down
-- that's a safety feature.

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2-14 How to Start the Engine
1. Without pushing the accelerator pedal, turn your
ignition key to START. When the engine starts, let
go of the key. The idle speed will go down as your
engine gets warm.
NOTICE:
Holding your key in START for longer than
15 seconds at a time will cause your battery to
be drained much sooner. And the excessive heat
can damage your starter motor. Wait about
15 seconds between each try to help avoid
draining your battery or damaging your starter.
2. If it doesn't start right away, hold your key in
START. If it doesn't start in 10 seconds, push the
accelerator pedal all the way down for five more
seconds, unless it starts sooner.3. If your engine still won't start (or starts but then
stops), wait 15 seconds and start over.
When the engine starts, let go of the key and the
accelerator pedal.
NOTICE:
Your engine is designed to work with the
electronics in your vehicle. If you add electrical
parts or accessories, you could change the way
the engine operates. Before adding electrical
equipment, check with your dealer. If you don't,
your engine might not perform properly.
If you ever have to have your vehicle towed, see
the part of this manual that tells how to do it
without damaging your vehicle. See ªTowing
Your Vehicleº in the Index.

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2-15
Engine Coolant Heater (If Equipped)
In very cold weather,
0
F (
-18
C) or colder,
the engine coolant
heater can help. You'll
get easier starting and
better fuel economy
during engine warm
-up.
Usually, the coolant
heater should be
plugged in a minimum
of four hours prior to
starting your vehicle.
To Use the Engine Coolant Heater
1. Turn off the engine.
2. Open the hood and unwrap the electrical cord.
The engine coolant heater electrical cord is located
on the driver's side of the engine compartment, near
the power steering reservoir.3. Plug it into a normal, grounded 110
-volt AC outlet.
CAUTION:
Plugging the cord into an ungrounded outlet
could cause an electrical shock. Also, the wrong
kind of extension cord could overheat and cause
a fire. You could be seriously injured. Plug the
cord into a properly grounded three
-prong
11 0
-volt AC outlet. If the cord won't reach, use a
heavy
-duty three-prong extension cord rated for
at least 15 amps.
4. Before starting the engine, be sure to unplug and store
the cord as it was before to keep it away from moving
engine parts. If you don't, it could be damaged.
How long should you keep the coolant heater plugged
in? The answer depends on the outside temperature, the
kind of oil you have, and some other things. Instead of
trying to list everything here, we ask that you contact
your dealer in the area where you'll be parking your
vehicle. The dealer can give you the best advice for that
particular area.

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2-16
Automatic Transmission Operation
There are several different positions for your shift lever.
If your vehicle is equipped with an automatic
transmission, it features an electronic shift position
indicator within the instrument cluster. This display
must be powered any time the shift lever is capable of
being moved out of PARK (P). This means that if your
key is in OFF, rather than LOCK, there will be a small
current drain on your battery which could discharge
your battery over a period of time. If you have to leave
your key in the ignition in OFF for an extended period,
it is recommended that you disconnect the battery cable
from the battery to prevent discharging your battery.
PARK (P): This locks your rear 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 firmly set. Your vehicle can roll.
Don't 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 won't move, even when you're on fairly
level ground, always set your parking brake
and move the shift lever to PARK (P).
If you have four-wheel drive, your vehicle
will be free to roll
-- even if your shift lever
is in PARK (P)
-- if your transfer case is in
NEUTRAL (N). So, be sure the transfer case is
in a drive gear, two
-wheel high (2H) or
four
-wheel high (4H) or four-wheel low
(4L)
-- not in NEUTRAL (N). See ªShifting
Into PARK (P)º in the Index. If you're pulling
a trailer, see ªTowing a Trailerº in the Index.

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2-17
REVERSE (R): Use this gear to back up.
NOTICE:
Shifting to REVERSE (R) while your vehicle
is moving forward could damage your
transmission. 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
ªStuck: In Sand, Mud, Ice or Snowº in the Index.
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 out of PARK (P) or NEUTRAL (N) while
your engine is ªracingº (running at high speed) is
dangerous. Unless your foot is firmly on the
brake pedal, your vehicle could move very
rapidly. You could lose control and hit people or
objects. Don't shift out of PARK (P) or
NEUTRAL (N) while your engine is racing.
NOTICE:
Damage to your transmission caused by shifting
out of PARK (P) or NEUTRAL (N) with the
engine racing isn't covered by your warranty.

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2-18
AUTOMATIC OVERDRIVE (
): This position is
for normal driving. If you need more power for passing,
and you're:

Going less than about 35 mph (56 km/h), push your
accelerator pedal about halfway down.

Going about 35 mph (56 km/h) or more, push the
accelerator all the way down.
You'll shift down to the next gear and have more power.
AUTOMATIC OVERDRIVE (
) 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 AUTOMATIC OVERDRIVE (
).
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 off and on.If you manually select SECOND (2), the transmission
will drive in second gear. You may use this feature
for reducing torque to the rear wheels when you are
trying to start your vehicle from a stop on slippery
road surfaces.
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
selector lever is put in FIRST (1) while the vehicle is
moving forward, the transmission won't shift into first
gear until the vehicle is going slowly enough.
NOTICE:
If your rear wheels can't rotate, don't try to
drive. This might happen if you were stuck in
very deep sand or mud or were up against a solid
object. You could damage your transmission.
Also, if you stop when going uphill, don't hold
your vehicle there with only the accelerator
pedal. This could overheat and damage the
transmission. Use your brakes or shift into
PARK (P) to hold your vehicle in position
on a hill.

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2-19
Manual Transmission Operation
5-Speed (If Equipped)
Here's how to operate
your transmission.
FIRST (1) is intended only for heavy loads and is not
recommended for normal driving.
During the first 500 miles (805 km) of vehicle use, start
your vehicle moving in FIRST (1). This allows clutch
components to break
-in properly.
FIRST (1): Press the clutch pedal and shift into
FIRST (1). Then, slowly let up on the clutch pedal as
you press the accelerator pedal. Shift into FIRST (1)
only when the vehicle is below 5 mph (8 km/h). If you
try to shift down into FIRST (1) at excessive vehicle
speeds, the shift lever will not move into the FIRST (1)
position until vehicle speed is reduced.SECOND (2): Press the clutch pedal and shift into
SECOND (2). Then, slowly let up on the clutch pedal as
you press the accelerator pedal.
You can shift into SECOND (2) when you're going less
than 20 mph (32 km/h). If you've come to a complete
stop and it's hard to shift into SECOND (2), put the shift
lever into NEUTRAL (N) and let up on the clutch.
Press the clutch pedal back down. Then shift into
SECOND (2). If you try to downshift into SECOND (2)
at excessive vehicle speeds, the shift lever will not move
into the SECOND (2) position until the vehicle speed
is reduced.
THIRD (3): Press the clutch pedal and shift into
THIRD (3). Then, slowly let up on the clutch pedal as
you press the accelerator pedal.
FOURTH (4) and FIFTH (5): Shift into the higher
forward gears the same way you do for THIRD (3).
Slowly let up on the clutch pedal as you press the
accelerator pedal.
To stop, let up on the accelerator pedal and press the
brake pedal. Just before the vehicle stops, press the
clutch pedal and the brake pedal, and shift to
NEUTRAL (N).

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2-20
NEUTRAL (N): Use this position when you start or
idle your engine.
REVERSE (R): To back up, first press down the clutch
pedal. Wait about five seconds for the internal parts to
stop spinning, and then shift into REVERSE (R).
Let up on the clutch pedal slowly while pressing the
accelerator pedal.
NOTICE:
Shift to REVERSE (R) only after your vehicle is
stopped. Shifting to REVERSE (R) while your
vehicle is moving could damage your transmission.
Also, use REVERSE (R), along with the parking brake,
when turning off your engine and parking your vehicle.
Shift Speeds
CAUTION:
If you skip more than one gear when you
downshift, you could lose control of your vehicle.
You could injure yourself or others. Don't shift
down more than one gear at a time when you
down shift.
If your speed drops below 20 mph (32 km/h), or if the
engine is not running smoothly, you should downshift to
the next lower gear. You may have to downshift two or
more gears to keep the engine running smoothly or for
good performance.

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2-21
Up Shift Light
If you have a manual
transmission, you may have
a SHIFT light. This light
will show you when to shift
to the next higher gear for
best fuel economy.
When this light comes on, you can shift to the next
higher gear if weather, road and traffic conditions let
you. For the best fuel economy, accelerate slowly and
shift when the light comes on.
While you accelerate, it is normal for the light to go on
and off if you quickly change the position of the
accelerator. Ignore the SHIFT light when you downshift.
If your vehicle has four
-wheel drive and is equipped
with a manual transmission, disregard the SHIFT light
when the transfer case is in 4
-Wheel Low.
Four-Wheel Drive (If Equipped)
If your vehicle has four-wheel drive, you can send your
engine's driving power to all four wheels for extra
traction. To get the most satisfaction out of four
-wheel
drive, you must be familiar with its operation. Read the
part that follows before using four
-wheel drive. You
should use 2
-WHEEL HIGH (2H) for most normal
driving conditions.
NOTICE:
Driving in the 4-WHEEL HIGH (4H) or
4
-WHEEL LOW (4L) positions for a long time
on dry or wet pavement could shorten the life of
your vehicle's drivetrain.

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2-22 Front Axle Locking Feature
The front axle locks and unlocks automatically when
you shift the transfer case. Some delay for the axle to
lock or unlock is normal.
Manual Transfer Case (If Equipped)
The transfer case shift lever is on the floor to the right of
the driver. Use this lever to shift into and out of
four
-wheel drive.
The front axle portion of the indicator diagram will light
up when you shift into four
-wheel drive and the front
axle engages.
Some delay between shifting and the indicator's lighting
is normal. If the front axle light does not go out
immediately after you shift out of four
-wheel drive,
have your dealer check your system.
An indicator near the lever shows you the transfer
case settings:
2
-Wheel High (2H): This setting is for driving in most
street and highway situations. Your front axle is not
engaged in two
-wheel drive.