automatic transmission GMC C-SERIES 1999 User Guide

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2-24 Hydraulic Brakes
If your vehicle has hydraulic brakes, it has a parking
brake lever or an electric/hydraulic parking brake. The
lever is below the instrument panel to the left of the
steering column. The electric/hydraulic parking brake
knob is to the right of the steering column.
Your vehicle may also be equipped with an automatic
transmission which has a shift lever. This lever will have
a PARK (P) position on the shift indicator. When the
PARK (P) position is selected with the shift lever, the
parking brake is automatically applied.
Propshaft Brake Burnish Procedure
It is recommended that the propshaft-mounted parking
brake be burnished as part of the new vehicle break
-in.
The parking brake will work best after it has been
burnished following these instructions.
Make 10 stops, using the parking brake hand lever, from
20 mph (32 km/h) about 2 1/2 miles (4 km) apart.
Between stops, drive the vehicle at 20 mph (32 km/h).
Lever Operated Parking Brake
To apply the parking brake,
pull the lever all the way up.
The PARK BRAKE light
will come on when the
parking brake is applied.
Then shift the transmission
to NEUTRAL (N) or
PARK (P).
The vehicle must be stopped when applying the parking
brake, except while burnishing the parking brake linings
(see ªPropshaft Brake Burnish Procedureº in the Index).
You can easily adjust the parking brake by turning the
knob on the lever. Turning it clockwise makes the brake
grip more tightly. It will also make the lever seem harder
to pull up. Turning the knob counterclockwise makes the
parking brake apply less firmly. Adjust the parking
brake only when the lever is down (released).
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2-25
If your parking brake doesn't hold the vehicle when
applied, see your GM Truck dealer who can adjust your
parking brake properly.
To release the parking
brake, first push down the
regular brake pedal. Then,
push the parking brake lever
all the way down and shift
the automatic transmission
to NEUTRAL (N).
The PARK BRAKE light will remain illuminated if the
parking brake is not fully released.
NOTICE:
Driving with the parking brake on can overheat
the parts in the system. You may have to replace
them, and you could also damage other parts of
your vehicle.
Electric/Hydraulic Parking Brake
(If Equipped)
CAUTION:
It will take a few seconds for the parking brake
to fully apply, and even longer when it is cold
outside. Do not leave your vehicle until the
parking brake applies fully. Without the parking
brake applied, your vehicle is free to move. It
could hit someone or something.
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2-26
If your vehicle has this
system, you will have a
knob to the right of the
steering column.
To apply the parking brake, pull the knob toward you.
Then shift the transmission to NEUTRAL (N) or
PARK (P).
Push the knob in to release the parking brake. The
ignition must be in RUN and the shift lever out of
PARK (P) in order to release the parking brake.
The parking brake will automatically apply if the
ignition is turned off and in PARK (P) and will also
apply (will not release) if the vehicle's battery is dead
or disconnected.The PARK BRAKE light may flash while the parking
brake is being applied or released. This is normal for
this system.
If your vehicle needs towing or the parking brake will
not release, the towing operator will need to disconnect
the propshaft before towing your vehicle. See ªTowing
Your Vehicleº in the Index.
Air Brake (If Equipped)
CAUTION:
When the yellow SYSTEM PARK and the red
TRAILER AIR SUPPLY knobs are both pushed
in, your rig will be free to move. It could strike
someone or something. When both of these knobs
are pushed in, either hold the regular brake
pedal down or, if you have it, pull out the blue
TRACTOR PARKING knob, to keep your rig
from moving.
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2-28
CAUTION:
If you apply any one of the air brake parking
controls while the vehicle is moving, your rig will
stop suddenly. If you are not ready for this, you
or others could be injured. Don't apply any one
of these controls while you're driving, unless you
have to make an emergency stop.
If the air pressure drops below 60 to 70 psi (413 to
482 kPa), the PRIMARY BRAKE light will come on. If
the air pressure drops to 40 to 45 psi (275 to 309 kPa), the
yellow knob will automatically pop out and apply the
spring brakes. If you ever have a complete loss of air so
that your air brakes automatically apply, there is a way that
the tow operator can release the parking brakes to tow the
vehicle. See ªTowing Your Vehicleº in the Index.
CAUTION:
If your vehicle is left in gear, the engine can
start if the vehicle starts to roll. This can easily
happen if you have the diesel engine. Shift the
transmission into NEUTRAL (N) before you
leave the vehicle.
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2-30
Running Your Engine While You're
Parked (Automatic Transmission)
It's better not to park with the engine running. But if
ever you 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
ªEngine Exhaustº).
Also, idling in a closed-in place can let deadly
carbon monoxide (CO) into your vehicle even if
the fan switch 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.
(See ªBlizzardº in the Index.)
CAUTION:
It can be dangerous to get out of your vehicle
without the parking brake firmly set. Your
vehicle can roll. If you've 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.
Follow the proper steps to be sure your vehicle
won't move.
Windows
Manual Windows
Turn the hand crank on each door to raise or lower
the window.
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2-36 Cruise Control (If Equipped)
With cruise control, you can
maintain a speed of about
30 mph (48 km/h) or more
without keeping your foot
on the accelerator. Cruise
control does not work at
speeds below about 30 mph
(48 km/h).
If you have an automatic transmission and you apply
your brakes, the cruise control will shut off.
If you have a manual transmission and you apply your
brakes or push the clutch pedal, the cruise control will
shut off.CAUTION:

Cruise control can be dangerous where you
can't drive safely at a steady speed. So,
don't use your cruise control on winding
roads or in heavy traffic.

Cruise control can be dangerous on
slippery roads. On such roads, fast changes
in tire traction can cause needless wheel
spinning, and you could lose control. Don't
use cruise control on slippery roads.
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2-57
Readings in the low warning zone may occur when a
large number of electrical accessories are operating
in the vehicle and the engine is left at an idle for an
extended period. This condition is normal since the
charging system may not be able to provide full
power at engine idle. As engine speeds are increased,
this condition should correct itself because higher
engine speeds allow the charging system to create
maximum power.
You can only drive a short time on the battery. Be sure
to shut off the radio, the fan or any unnecessary
accessories and have the system serviced.
Do Not Shift Warning Light
If your vehicle has the
Allison MD automatic
transmission, certain
transmission malfunctions
will turn this light on.If this light comes on while you are driving, do not use
the transmission shift control. Using the transmission
shift control will result in the loss of forward gears. The
computer for the transmission senses a problem and
chooses a gear to stay in so that you can drive the
vehicle in that gear. You may not be able to drive as fast
or back up when this light is on.
NOTICE:
If the DO NOT SHIFT warning light comes on
while you are driving, it is a warning that making
a transmission ªrangeº change could leave you
stranded. The vehicle may not continue to move
if you change gears with the transmission shift
control. The transmission can't operate in all
gears because something is wrong. Leave the shift
control alone and drive directly to a GM dealer
for service. If you can't go in for service
immediately, have the vehicle towed.
Brake System Warning Light
Your vehicle has either hydraulic or air brakes. Each
system has different warning lights.
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2-69 Transmission Temperature Gage
(If Equipped)
If you have an automatic
transmission and this gage,
it is to the right of the dash
mounted shift lever, just to
the right of your
floor
-mounted shift lever or
on the lower portion of the
instrument panel to the right
of the steering wheel.
When your ignition is on, the gage shows the
temperature of the transmission oil. A reading in the
warning zone means you must stop driving and check
into the cause. One possible cause is a low oil level in
the transmission.
NOTICE:
If you drive when the transmission temperature
gage is in the warning zone, you can badly
damage the transmission.
Air Pressure Gage (If Equipped)
If your vehicle has air
brakes, this gage at the
center of your instrument
cluster shows the air
pressure for both your front
and rear brake systems.
If the needle on the gage indicates that the air pressure is
below 60 psi (415 kPa), the LOW AIR warning light
will come on. An alarm will also sound if this happens.
The yellow pointer shows the pressure available for the
front system, while the green pointer shows pressure for
the rear. There should be no more than 4 psi (28 kPa)
difference showing between the systems.
Don't drive until both pointers are showing at least
120 psi (830 kPa), so you'll have enough air if you need
to apply your brakes.
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5-19 If No Steam Is Coming From Your Engine
If you get an engine overheat warning but see or hear no
steam, the problem may not be too serious. Sometimes
the engine can get a little too hot when you:

Climb a long hill on a hot day.

Stop after high
-speed driving.

Idle for long periods in traffic.
If you get the overheat warning with no sign of steam,
try this for a minute or so:
1. If you have an air conditioner and it's on, turn it off.
2. Turn on your heater to full hot at the highest fan
speed and open the window as necessary.
3. If you're in a traffic jam, shift to NEUTRAL (N);
otherwise, shift to the highest gear while
driving
-- DRIVE (D) for automatic transmissions.
4. If climbing a hill, downshift to raise engine and
fan speeds.If you no longer have the overheat warning, you can
drive. Just to be safe, drive slower for about 10 minutes.
If the warning doesn't come back on, you can
drive normally.
If the warning continues, pull over, stop, and park your
vehicle right away.
If there's still no sign of steam, push down the
accelerator until the engine speed is about twice as fast
as normal idle speed for at least three minutes while
you're parked. If you still have the warning, turn off the
engine and get everyone out of the vehicle until it
cools down.
You may decide not to lift the hood but to get service
help right away.
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6-
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6-1
Section 6 Service and Appearance Care
Here you will find information about the care of your vehicle. This section begins with service and fuel information,
and then it shows how to check important fluid and lubricant levels. There is also technical information about your
vehicle, and a part devoted to its appearance care.
6
-2 Service
6
-4 Fuel (Gasoline Engine)
6
-5 Diesel Fuel Requirements and Fuel System
6
-6 Fuels in Foreign Countries (Gasoline Engines)
6
-7 Filling Your Tank
6
-8 Filling a Portable Fuel Container
6
-9 Checking Things Under the Hood
6
-11 Noise Control System
6
-13 Engine Oil (Gasoline Engine)
6
-17 Engine Oil (Caterpillar
Diesel Engine)
6
-17 Engine Air Cleaner/Filter
6
-18 Automatic Transmission Fluid
6
-19 Manual Transmission Fluid
6
-20 Rear Axle
6
-20 Rear Axle Shift Motor (Option)
6
-21 Radiator Pressure Cap (Gasoline Engines)
6
-22 Surge Tank Pressure Cap (Diesel Engines)
6
-22 Thermostat6
-23 Engine Coolant (Gasoline Engine)
6
-27 Engine Coolant (Caterpillar
Diesel Engine)
6
-28 Power Steering Fluid
6
-29 Windshield Washer Fluid
6
-30 Brakes
6
-36 Electric/Hydraulic Parking Brake Fluid
6
-42 Battery
6
-44 Other Service Items
6
-48 Tires
6
-59 Appearance Care
6
-59 Cleaning the Inside of Your Vehicle
6
-63 Cleaning the Outside Your Vehicle
6
-66 GM Vehicle Care/Appearance Materials
6
-67 Vehicle Identification Number (VIN)
6
-67 Service Parts Identification Label
6
-68 Electrical System
6
-74 Capacities and Specifications
6
-77 Air Conditioning Refrigerants
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