transmission GMC SIERRA CLASSIC 2007 Owner's Manual

Cruise Grade Braking is available on the 6.6L
DURAMAX®diesel engine. Cruise Grade Braking
monitors a vehicle’s cruise state, engine torque,
acceleration, vehicle speed, and the cruise set
speed. Using this information, it detects when the
truck is accelerating on a downhill grade and will
automatically downshift to slow the vehicle if it
exceeds the cruise set speed by a certain amount.
SeeCruise Control on page 217for more
information.
The Tow/Haul mode and Grade Braking shift
modes can be activated by pressing the button on
the end of the shift control stalk. If your vehicle
has the DURAMAX
®diesel Engine or the
8.1L VORTEC™ gasoline engine, Grade Braking
is only available while the Tow/Haul Mode is
selected. While in the Range Selection Mode,
Grade Braking is deactivated allowing the driver to
select a desired range of gears.
SeeAutomatic Transmission Operation on
page 140for more information.
Also seeTowing a Trailer on page 429for more
information.
Manual Transmission Operation
Five-Speed
(VORTEC™ 6.0L V8 Engine)
Here is how to operate
your transmission.
FIRST (1) is intended only for heavy loads or
trailer towing and is not recommended for normal
driving.
During the rst 500 miles (805 km) of vehicle use,
start your vehicle moving in FIRST (1). This
allows clutch components to break-in properly.
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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).
Notice:If you try to shift down into FIRST (1) at
excessive vehicle speeds, clutch or engine
damage could occur. Do not shift into FIRST (1)
unless you are going less than 5 mph (8km/h).
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 are going
less than 20 mph (32 km/h). If you have come to a
complete stop and it is hard to shift into
SECOND (2), put the shift lever into NEUTRAL and
let up on the clutch. Press the clutch pedal back
down. Then shift into SECOND (2).
Notice:If you try to shift down into
SECOND (2) at excessive vehicle speeds,
clutch or engine damage could occur. Do not
shift into SECOND (2) unless you are going
less than 20 mph (32km/h).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.
NEUTRAL:Use this position when you start or
idle your engine.
REVERSE (R):To back up, rst press down the
clutch pedal. Wait for the vehicle to stop moving
and then, shift into REVERSE (R). Let up on
the clutch pedal slowly while pressing the
accelerator pedal.
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.
150

Also, use REVERSE (R), along with the parking
brake, when turning off your engine and parking
your vehicle.
Five-Speed (VORTEC™ 4.3L V6 and
4.8L V8 Engines)
Here is how to operate your transmission:
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.
You can shift into FIRST (1) when you are going
less than 20 mph (32 km/h). If you have come to a
complete stop and it is hard to shift into FIRST (1),
put the shift lever into NEUTRAL and let up on
the clutch. Press the clutch pedal back down. Then
shift into FIRST (1).
Notice:If you try to shift down into FIRST (1)
at excessive vehicle speeds, clutch or
engine damage could occur. Do not shift into
FIRST (1) unless you are going less than
20 mph (32km/h).
SECOND (2):Press the clutch pedal as you let
up on the accelerator pedal and shift into
SECOND (2). Then, slowly let up on the clutch
pedal as you press the accelerator pedal.THIRD (3), FOURTH (4) and FIFTH (5):Shift into
THIRD (3), FOURTH (4) and FIFTH (5) the same
way you do for SECOND (2). 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.
NEUTRAL:Use this position when you start or
idle your engine.
REVERSE (R):To back up, rst press down the
clutch pedal. Wait for the vehicle to stop moving
and then, shift into REVERSE (R). Let up on
the clutch pedal slowly while pressing the
accelerator pedal.
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.
Also, use REVERSE (R), along with the parking
brake, when turning off your engine and parking
your vehicle.
151

Shift Speeds
{CAUTION:
If you skip a gear when you downshift,
you could lose control of your vehicle.
You could injure yourself or others. Do
not shift down more than one gear at a
time when you downshift.
Do not allow the engine Revolutions Per Minute
(RPM) to overspeed and enter the tachometer red
lines. Engine overspeed occurs when downshifting,
or descending a grade, at too high a vehicle
speed. When going down steep grades, always
select a gear at least one position lower than you
would use on climbing a grade. This will allow
the vehicle’s engine to provide some braking and
help to slow the vehicle as it goes down the
grade. Monitor your vehicle speed, acceleration
and engine RPM while applying the brakes as you
go down the grade to ensure you have complete
control over the vehicle.If your engine speed drops below 600 rpm, or if
the engine is not running smoothly, you should
downshift to the next lower gear. When operating
on slippery surfaces, downshift at lower than
normal vehicle speeds to prevent the tires from
slipping.
In vehicles that have a bench seat, move the
tallest beverage containers to the right cupholder
to provide additional clearance for the shift
lever.
For vehicles that have a center console, the front
cup holder pulls out and turns 180° to provide
additional clearance between tall beverage
containers and the shift lever.
Up-Shift Light
If your vehicle has 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.
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When this light comes on, you can shift to the next
higher gear if weather, road and traffic conditions
allow. 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.
If your vehicle has four-wheel drive and has a
manual transmission, disregard the shift light when
the transfer case is in Four-Wheel Low.
Ignore the shift light when you downshift.
Four-Wheel Drive
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. See the appropriate text for
the transfer case in your vehicle.
While driving on clean dry pavement and during
tight turns, you may experience a vibration in
the steering system.
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
The transfer case shift lever is located on the oor
to the right of the driver. Use this lever to shift
into and out of four-wheel drive.
153

A 4WD indicator light
comes on when you
shift into four-wheel
drive and the front axle
engages. See
Four-Wheel-Drive Light
on page 263.
Some delay between shifting and when the
indicator light comes on is normal.
Recommended Transfer Case Settings
Driving ConditionsTransfer Case Settings
2H 4H 4L N
Normal YES
Severe YES
Extreme YES
Vehicle in Tow* YES
*SeeRecreational Vehicle Towing on page 424or
Towing Your Vehicle on page 423for further
information.
An indicator light near the lever shows you the
transfer case settings:
Notice:Driving on clean, dry pavement in
four-wheel drive for an extended period of time
may cause premature wear on your vehicle’s
powertrain. Do not drive on clean, dry
pavement in four-wheel drive for extended
periods of time.
4L (Four-Wheel Low):This setting also engages
the front axle and delivers extra torque. You
may never need 4L. It sends maximum power to
all four wheels. You might choose 4L if you
are driving off-road in deep sand, deep mud, deep
snow, and while climbing or descending steep
hills. When operating in 4L, the gear ratio provides
additional torque when compared to 4H. The
transmission gear shift feel will be exaggerated.
154

{CAUTION:
Shifting the transfer case to NEUTRAL
can cause your vehicle to roll even if the
transmission is in PARK (P), or if you
have a manual transmission, even if you
are in gear. You or someone else could be
seriously injured. Be sure to set the
parking brake before placing the transfer
case in NEUTRAL. SeeParking Brake on
page 169.
N (Neutral):Shift to this setting only when your
vehicle needs to be towed. SeeRecreational
Vehicle Towing on page 424orTowing Your
Vehicle on page 423.2H (Two-Wheel Drive High):This setting is used
for driving in most street and highway situations.
The front axle is not engaged in two-wheel
drive. This setting also provides the best fuel
economy.
4H (Four-Wheel Drive High):Use this setting
when you need extra traction, such as on snowy or
icy roads or in most off-road situations. This
setting also engages the front axle to help drive
your vehicle. This is the best setting to use
when plowing snow.
You can shift from 2H to 4H or 4H to 2H while the
vehicle is moving. The front axle will engage
faster if you take your foot off of the accelerator
for a couple of seconds after you shift. In
extremely cold weather, it may be necessary to
stop or slow the vehicle to shift into 4H.
155

Shifting In or Out of 4L (Four-Wheel
Drive Low)
Notice:Shifting the transfer case into 4L
while moving at speeds faster than 3 mph
(5 km/h) may cause premature wear to
the transfer case, and may cause the gears to
grind. To avoid causing premature wear,
and grinding the gears, do not shift the transfer
case into 4L while the vehicle is moving
faster than 3 mph (5 km/h).
Shifts into 4L can be made with the vehicle at a
stop, or while slowly rolling about 1 to 3 mph
(2 to 5 km/h).
Shift the automatic transmission into
NEUTRAL (N), or with a manual transmission,
press the clutch pedal, or shift into NEUTRAL.
Shift the transfer case shift lever in one
continuous motion into the 4L position.
When in 4L do not drive faster than 45 mph.
This will reduce wear and extend the life of
the transfer case.
Shifting In or Out of NEUTRAL
1. With the vehicle running and the engine at an
idle set the parking brake and apply the
regular brake.
2. Place the transmission into NEUTRAL (N).
Shift the transfer case in one continuous motion
into or out of the NEUTRAL position.
Automatic Transfer Case
The transfer case
buttons are located to
the left of the instrument
panel cluster.
Use these switches to shift into and out of
four-wheel drive.
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Recommended Transfer Case Settings
Driving
ConditionsTransfer Case Settings
2
mAUTO
4WD4m4nN
Normal YES
Variable YES
Severe YES
Extreme YES
Vehicle in
Tow*YES
*SeeRecreational Vehicle Towing on page 424for
further information.
You can choose among ve driving settings:
Notice:Driving on clean, dry pavement in
Four-Wheel-Drive High or Four-Wheel-Drive
Low for an extended period of time may cause
premature wear on your vehicle’s powertrain.
Do not drive on clean, dry pavement in
Four-Wheel-Drive High or Four-Wheel-Drive
Low for extended periods of time.Indicator lights in the switches show the current
setting. The indicator lights will come on briey
when you turn on the ignition and the last chosen
setting will stay on. If the lights do not come
on, you should take your vehicle to your dealer for
service. An indicator light will ash while shifting.
Fast ashing means the conditions are not
being met to make the desired shift, typically the
vehicle is going too fast, the automatic
transmission is not in NEUTRAL, or the clutch
pedal is not fully pressed. Slow ashing means the
shift is in progress. It will stay on when the shift
is completed. If for some reason the transfer case
cannot make a requested shift, it will return to
the last chosen setting.
AUTO 4WD (Automatic Four-Wheel Drive):This
setting is ideal for use when road surface
traction conditions are variable. When driving your
vehicle in AUTO 4WD, the front axle is engaged,
but the vehicle’s power is primarily sent to the rear
wheels. When the vehicle’s software determines
a need for more traction, the system will
transfer more power to the front wheels. Driving in
this mode results in slightly lower fuel economy
than Two-Wheel Drive High.
158

2m(Two-Wheel Drive High):This setting is
used for driving in most street and highway
situations. Your front axle is not engaged in
two-wheel drive. This setting also provides the best
fuel economy.
{CAUTION:
Shifting the transfer case to NEUTRAL
can cause your vehicle to roll even if the
transmission is in PARK (P). You or
someone else could be seriously injured.
Be sure to set the parking brake before
placing the transfer case in NEUTRAL.
SeeParking Brake on page 169.
N (NEUTRAL):Shift the vehicle’s transfer case to
N (NEUTRAL) only when towing your vehicle.
SeeRecreational Vehicle Towing on page 424or
Towing Your Vehicle on page 423for more
information.4
m(Four-Wheel Drive High):Use this setting
when you need extra traction, such a on snowy
or icy roads or in most off-road situations.
This setting also engages your front axle to help
drive the vehicle. This is the best setting to
use when plowing snow.
4
n(Four-Wheel Drive Low):This setting also
engages the front axle and delivers extra
torque. You may never need Four-Wheel Drive
Low. It sends maximum power to all four wheels.
You might choose Four-Wheel Drive Low if
you are driving off-road in deep sand, deep mud,
deep snow, and while climbing or descending
steep hills. When operating in Four-Wheel Drive
Low, the gear ratio provides additional torque
when compared to Four-Wheel Drive High. The
transmission gear shift feel will be exaggerated.
If the SERVICE 4WD message stays on the Driver
Information Center (DIC), you should take your
vehicle to your dealer for service. SeeDIC
Warnings and Messages on page 270for further
information.
159