engine CHEVROLET C/K 2003 Owner's Manual

2-35
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 equipped.
CAUTION:
Shifting into a drive gear 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
into a drive gear while your engine is racing.

2-36 Overdrive Defeat (If Equipped)
If your vehicle has this feature, you can select not to
shift up to fifth gear. This is useful when towing or
under a heavy load.
The overdrive defeat switch
is located in the instrument
panel to the right of the
steering column.
Press the switch to limit the transmission to fourth gear.
This will allow for better fuel economy and fewer
downshifts while pulling a tractor or trailer or under a
heavy load. The indicator light in the switch will come
on whenever overdrive defeat is active.
Manual Transmission Operation
Using the Clutch
When you're starting to move the vehicle, it's important
to begin with the engine speed at idle. Then start to
engage the clutch and listen for an engine speed drop
of about 100 rpm. At this point, the clutch is engaging,
so you should increase the engine speed and fully
engage the clutch. It's important not to increase the
engine speed sooner or before the clutch begins it's
engagement. If you do, you can cause damage to
your vehicle.
Double-Clutching
You must use the double-clutching method when you
shift an unsynchronized gear set. Disengage the clutch,
shift to neutral and engage the clutch. When upshifting,
slow the engine until the engine rpm and road speed
match. When downshifting, accelerate the engine until
the engine rpm and road speed match. Then quickly
disengage the clutch and move the shift lever to the next
gear position and engage the clutch.

2-37 Eaton Fuller Five and Six-Speed
Transmissions and TTC Spicer
Seven-Speed Transmissions
These transmissions have gears that automatically
synchronize when you shift up or down (except
FIRST (1) gear on the five
-speed and seven-speed
transmission which is unsynchronized). Choose the gear
that will maintain the road speed you want while
keeping the engine above two
-thirds of the governed
speed. When the engine speed drops below two
-thirds of
the governed speed, shift into the next lower gear before
your engine begins to lug. When you shift down, be sure
to double
-clutch if required.
ZF Six-Speed Transmission
Here's how to operate
your transmission.
This six
-speed pattern is unique to GM manual
transmissions. The transmission always repositions
the shift lever to neutral, which is located between
FOURTH (4) and FIFTH (5) gear.
To prevent unintentional gear selections, additional
force is required to move the shift lever into
REVERSE (R) or FIRST (1). Use FIRST (1) when
trailer towing, driving with payload in the pickup box or
launching on a grade. Otherwise, start in SECOND (2)
gear. Only shift into FIRST (1) when the vehicle has
stopped moving.

2-38
During the first 500 miles (805 km) of vehicle use, start
the vehicle moving in FIRST (1) gear. This allows the
clutch components to wear
-in properly.
FIRST (1): With the vehicle at a stop, release the brake,
press the clutch pedal and shift into FIRST (1). Then,
slowly let up on the clutch pedal as you press the
accelerator pedal. Only downshift into FIRST (1) when
the vehicle has come to a complete stop. If the shift
lever will not go into FIRST (1), put the lever in neutral
and let up on the clutch pedal to fully engage the clutch.
Press the clutch pedal again. Then, shift into FIRST (1).
SECOND (2): With the vehicle at a stop, release the
brake, press the clutch pedal and shift into
SECOND (2). Then, slowly let up on the clutch pedal as
you press the accelerator pedal. With the vehicle
moving, press the clutch pedal and upshift into
SECOND (2) from FIRST (1) while applying light
pressure to the right on the shifter. Then, slowly let up
on the clutch pedal as you press the accelerator pedal.
If you come to a complete stop and the shift lever will
not go into SECOND (2), put the lever in neutral and let
up on the clutch pedal to fully engage the clutch. Press
the clutch pedal again. Then, shift into SECOND (2).THIRD (3): Press the clutch pedal and upshift into
THIRD (3). Then, slowly let up on the clutch pedal as
you press the accelerator pedal.
FOURTH (4), FIFTH (5) and SIXTH (6): Upshift
into the higher forward gears the same way as you do
THIRD (3). Slowly let up on the clutch pedal as you
press the accelerator pedal.
NEUTRAL: Use this position when you start or idle
your engine.
REVERSE (R): To back up, press the clutch pedal.
Wait for the vehicle to stop moving and then, shift to
REVERSE (R). Let up on the clutch slowly while
pressing the accelerator pedal. Also, use REVERSE (R),
along with the parking brake, when turning off your
engine and parking your vehicle.

2-39 Eaton Fuller Nine and Ten-Speed
Non-Synchronized Manual Transmissions
(If Equipped)
If your vehicle has one of these unsynchronized
transmissions, it's naturally somewhat complicated.
The label above the windshield will tell you the
operating basics you need to know.
The following are driving tips.

Always choose an initial starting gear suitable for
the load and terrain.

Always use double
-clutching procedures
when shifting.

Never move the range shift lever to the LO speed
gear position after HI range preselection, or anytime
the transmission is in the HI range.

Never move the range knob or lever with the shift
lever in NEUTRAL while the vehicle is moving.

Never make a range shift while moving
in REVERSE (R).
Clutch Brake (Vehicles with
Non-Synchronized Transmission)
A clutch brake is used to stop transmission input shaft
rotation so that FIRST (1) or REVERSE (R) gear
selection can be initiated when the vehicle is at a
standstill and the engine is idling.
Press the clutch pedal all the way down to the
floorboard to apply the clutch brake.
When using the clutch brake, disengage the clutch pedal
and shift the transmission into either the initial starting
gear or REVERSE (R). If the tooth
-butting occurs
between the clutching teeth, re
-engage the clutch while
applying light pressure to the shift lever. This will
provide for a smooth shift into either FIRST (1) or
REVERSE (R) gear.
NOTICE:
After engaging FIRST (1) or REVERSE (R) gear,
do not use the clutch brake for upshifting and
downshifting. To do so will shorten the service life
of the clutch brake and gear selection shift efforts
may be increased.

2-40
Parking
CAUTION:
If you don't park your vehicle properly, it can
roll. If you've left the engine running, it can move
very quickly. You or others could be injured. To
be sure your vehicle won't move, even when
you're on level ground, follow the steps below.
Two-Speed Rear Axle
1. With the engine running, shift the two-speed rear
axle into low. To be sure it's in low, you'll need to
move the vehicle in gear just a little.
2. Hold the regular brake pedal down with your
right foot.
3. Apply the parking brake.
4. Shift the transmission to NEUTRAL or PARK (P).
Hydraulic Brakes (If Equipped)
If your vehicle has hydraulic brakes, it has either a
parking brake foot pedal or hand lever. If you have the
parking brake foot pedal, it is located below the
instrument panel to the left of the steering column.
If you have the parking brake hand lever, it is located to
the right of the driver, on the floor.
To set the foot pedal parking brake, hold the regular
brake pedal down with your right foot. Push down the
parking brake pedal with your left foot.

2-44
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 and warning buzzer
will come on. If the air pressure drops to 35 to 45 psi
(241 to 310 kPa), the red trailer air supply knob will
automatically pop out and apply the spring brakes on
the trailer.If the air pressure drops to 35 to 45 psi (241 to 310 kPa),
the yellow park brake knob will automatically pop out
and apply the spring brakes on the truck or tractor.
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.

2-45
Parking Over Things That Burn
CAUTION:
Things that can burn could touch hot exhaust
parts under your vehicle and ignite. Don't 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't 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 weren't done correctly.

Your vehicle or exhaust system had been
modified 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 fixed immediately.

2-46
Running Your Engine While You're
Parked (Automatic Transmission)
It's 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 ªEngine
Exhaust.º
Also, idling in a closed-in place can let deadly
carbon monoxide (CO) into your vehicle even
if the 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.
See ªBlizzardº in the Index.
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 firmly set. Your vehicle can roll.
Don't leave your vehicle when the engine is
running unless you have to. 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 and
move the shift lever to PARK (P).

2-47
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.
Horn
Sound the horn by pushing the center of the steering
wheel. If you have the optional air horn, it is controlled
by a cord that you'll find up above and to the left of
the driver. The harder you pull on the cord, the louder
the air horn will sound. The air horn works only after
your air brake system pressure gets up to about
115 psi (790 kPa). The air horn will work properly
unless the the air brake system pressure drops
below 60 psi (415 kPa).