engine GMC C-SERIES 1999 Owner's Manual

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Manual Transmission Operation
This part of the manual covers the basics of the manual
transmission. With some of the transmissions, you
will find another manual in your vehicle that goes into
more detail.
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 its engagement.
If you do, you can cause damage to your vehicle.
Double-Clutching
You must use the ªdouble-clutchingº method when you
shift an unsynchronized gear set. Simply disengage the
clutch, shift to NEUTRAL (N) and engage the clutch.
When you're shifting down to a lower gear, accelerate
the engine speed while in NEUTRAL (N) to get ready
for the lower gear.
Eaton Fuller 5 and 6-Speed Transmissions
and Dana Spicer 7-Speed Transmissions
These transmissions have gears that automatically
synchronize when you shift up or down (except
FIRST (1) gear on the five
-speed transmission which is
unsynchronized). Choose the gear which 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.
Eaton Fuller 9 and 10-Speed
Manual Transmissions
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.
Before operating the vehicle with one of these
transmissions, be sure to read the Eaton Fuller
Transmission Driver Instructions Manual in your vehicle.
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2-23 Eaton Fuller Transmission with Clutch
Brake (Option)
Some vehicles have an optional clutch brake. It engages
when you push your clutch pedal all the way to the
floor. Use it when you shift into first or reverse gear.
Press the clutch pedal as far as it will go and then make
your shift. If the engagement isn't smooth when you
engage the clutch, press the clutch pedal in and then
immediately re
-engage it. Use the clutch brake only
with the engine idling and the vehicle standing still.
If you have this feature, see the Eaton Fuller
Transmission Driver Instructions Manual before
operating your vehicle.
Eaton Fuller Transmission with
Countershaft Brake (If Equipped)
The countershaft brake is used when you shift from a
standing start into FIRST (1) or REVERSE (R). You
will find this feature on vehicles with gasoline engines
and Eaton Fuller 9 or 10
-speed transmissions.
See the Eaton Fuller Transmissions Driver
Instructions Manual.
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 (N) or
PARK (P).
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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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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.
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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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Setting Cruise Control
CAUTION:
If you leave your cruise control switch on when
you're not using cruise, you might hit a button
and go into cruise when you don't want to. You
could be startled and even lose control. Keep the
cruise control switch off until you want to use it.
1. Move the cruise control switch to ON.
2. Get up to the speed you want.
3. Press in the SET button at the end of the lever and
release it.
4. Take your foot off the accelerator pedal.Resuming a Set Speed
Once you're going about 30 mph (48 km/h) or more,
you can move the cruise control switch from ON to
R/A (Resume/Accelerate) for about half a second.
The vehicle will return to your chosen speed and
stay there.
If you hold the switch at R/A longer than half a second,
the vehicle will keep going faster until you release the
switch or apply the brake, so unless you want to go
faster, don't hold the switch at R/A.
If the switch is held at R/A for longer than 200 seconds,
the cruise control will automatically turn off. The cruise
control function will be made available again the next
time the engine is restarted.
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Increasing Speed While Using Cruise Control
There are two ways to go to a higher speed:

Use the accelerator pedal to get to the higher speed.
Press the button at the end of the lever, then release
the button and the accelerator pedal. You'll now
cruise at the higher speed.

Move the cruise switch from ON to R/A. Hold it
there until you get up to the speed you want, and
then release the switch. To increase your speed in
very small amounts, move the switch to R/A for less
than half a second. Each time you do this, your
vehicle will go about 1 mph (1.6 km/h) faster.
If the switch is held at R/A for longer than
200 seconds, the cruise control will automatically
turn off. The cruise control function will be made
available again the next time the engine is restarted.Reducing Speed While Using Cruise Control
Press in the button at the end of the lever until you reach
the lower speed you want, then release it.
To slow down in very small amounts, tap the button for
less than half a second. Each time you do this, you'll go
1 mph (1.6 km/h) slower.
If the button is held for longer than 15 seconds, the
cruise control will automatically turn off. To make
cruise control available again, the cruise switch must be
moved to OFF then back to ON.
Passing Another Vehicle While Using Cruise Control
Use the accelerator pedal to increase your speed. When
you take your foot off the pedal, your vehicle will slow
down to the cruise control speed you set earlier.
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Let up on the accelerator before you turn on your rear
axle differential lock.
NOTICE:
Activating the rear-axle differential lock when
the rear wheels are actually spinning freely, as
they might on ice or snow, can cause you to lose
control of the vehicle. It can also damage the axle.
Turn on this control only when the wheels are not
spinning freely.
Engine Air Control (If Equipped)
If your vehicle has this control, the handle is located on
the instrument panel just to the right of the steering
wheel. The control is activated by pulling the handle out
and turning slightly in either direction to lock it.
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When the handle is pulled out, the engine air intake
supply is closed off from the front scoop and an under
hood air supply is opened. This control is intended only
for use in cold weather (32
F (0
C) or below) where
snow and ice might plug the external intake.
At temperatures above 32
F (0
C), keep the control
handle pushed in.
NOTICE:
Operating this vehicle with the engine air control
on when outside temperatures are above 32
F
(0
C), could lead to costly repairs not covered by
your warranty. It will also degrade fuel economy
and the engine will not run smoothly.
Exterior Lamps
Headlamps
The lamp switches are on the left side of your
instrument panel.
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Engine Speed Governor
All gasoline engines have a electronic engine speed
governor. The engine governed speeds range between
3600 and 4000 rpm depending on model, engine size
and option content.
Engine Road Speed Governor (Gasoline Engine)
This system controls maximum vehicle speed
automatically and reduces engine power until vehicle
speed gets down to maximum governed speed.
A 75 mph (120 km/h) road speed governor is
standard, but is optionally available in 60 or 65 mph
(97 or 105 km/h) speeds, depending on model.Tachometer (If Equipped)
Gasoline Engine Diesel Engine
This gage shows the engine speed in revolutions per
minute (rpm).
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