transmission CHEVROLET SILVERADO 2007 1.G User Guide

Grade Braking is not available when the Range
Selection Mode is active. SeeTow/Haul Mode on
page 146
While using the Range Selection mode feature,
cruise control and the Tow/Haul mode can
be used.
Notice:Spinning the tires or holding the
vehicle in one place on a hill using only the
accelerator pedal may damage the
transmission. The repair will not be covered by
your warranty. If you are stuck, do not spin
the tires. When stopping on a hill, use the
brakes to hold the vehicle in place.
Low Traction Mode
If your vehicle has the Allison Transmission®,or
the Hydra-Matic®6-Speed Automatic
Transmission, it has a Low Traction Mode that
assist in vehicle acceleration when road conditions
are slippery, such as with ice or snow. While
the vehicle is at a stop, select the second gear
range using the Range Selection system. This will
limit torque to the wheels after it detects wheel
slip, preventing the tires from spinning.
Tow/Haul Mode
If your vehicle has an automatic transmission, it
has a tow/haul mode. If your vehicle has an Allison
or Hydra-Matic
®6-speed automatic transmission
see “Tow/Haul Mode (Allison or Hydra-Matic®
6-Speed Automatic Transmission®) following.
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The tow/haul mode adjusts the transmission shift
pattern to reduce shift cycling, providing
increased performance, vehicle control, and
transmission cooling when towing or hauling
heavy loads.
The selector button is located on the end of the
shift lever. Turn the tow/haul on and off by
pressing the button. When the tow/haul is on, a
light on the instrument panel cluster will come on.
SeeTow/Haul Mode Light on page 268for
more information.
Also see Tow Haul Mode underTowing a Trailer
on page 447for more information.Tow/Haul Mode (Allison Transmission®
or Hydra-Matic®6-Speed Automatic
Transmission)
If your vehicle has an Allison or Hydra-Matic®
6-speed automatic transmission®, it has a tow/haul
mode. The tow/haul mode adjusts the transmission
shift pattern to reduce shift cycling, providing
increased performance, vehicle control, and
transmission cooling when towing or hauling
heavy loads.
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Turn the tow/haul mode on and off by pressing the
button, located on the end of the shift lever.
When the tow/haul is on, a light on the instrument
panel cluster will come on.
SeeTow/Haul Mode Light on page 268for more
information.
Also see “Tow Haul Mode” underTowing a Trailer
on page 447for more information.
Grade Braking (Allison Transmission®
or Hydra-Matic®6-Speed Automatic
Transmission)
The Grade Braking shift modes can be activated
by pressing the button on the end of the shift
control lever. While in Range Selection Mode,
Grade Braking is deactivated allowing the driver to
select a desired range of gears.Grade Braking is only active while the Tow/Haul
Mode is selected and you are not in the Range
Selection Mode. See “Tow/Haul Mode listed
previously andAutomatic Transmission Operation
on page 140for more information on the Range
Slection Mode. Grade Braking assists in
maintaining desired vehicle speeds when driving
on downhill grades by automatically implementing
a shift schedule that utilizes the engine and
transmission to slow the vehicle. This reduces
wear on the braking system and increases control
of the vehicle. Grade Braking monitors vehicle
speed, acceleration, engine torque and brake
pedal usage. Using this information, it detects
when the truck is on a downhill grade and
the driver desires to slow the vehicle by pressing
the brake. See the diesel supplement for
information on Cruise Grade Braking.
Also seeTowing a Trailer on page 447for more
information.
148

A Four-Wheel Drive
indicator light comes on
when you shift into
four-wheel drive and the
front axle engages.
SeeFour-Wheel-Drive
Light on page 267
Some delay between shifting and when the
indicator light comes on is normal.
Recommended Transfer Case Settings
Driving ConditionsTransfer Case Settings
2m4m4nN
Normal YES
Severe YES
Extreme YES
Vehicle in Tow* YES
*SeeRecreational Vehicle Towing on page 442
Towing Your Vehicle on page 441
Notice:Driving on clean, dry pavement in
four-wheel drive for an extended period of time
can cause premature wear on your vehicle’s
powertrain. Do not drive on clean, dry
pavement in Four-Wheel Drive for extended
periods of time.
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 Low,
the gear ratio provides additional torque when
compared to Four-Wheel-Drive High. The
transmission gear shift feel is exaggerated.
150

A parking brake symbol
is located next to the N
(NEUTRAL) symbol
as a reminder to set the
parking brake before
shifting the transfer case
in Neutral.
{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 164.N (NEUTRAL):Shift to this setting only when
your vehicle needs to be towed. SeeRecreational
Vehicle Towing on page 442orTowing Your
Vehicle on page 441
2
m(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.
4
m(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 Two-Wheel-Drive High to
Four-Wheel-Drive High or Four-Wheel-Drive High
to Two-Wheel-Drive High while the vehicle is
moving. In extremely cold weather, it may
be necessary to stop or slow the vehicle to shift
into Four-Wheel-Drive High.
151

When Using the Manual Transfer Case

Shifting should be made using quick
motions. Shifting slowly may make it more
difficult to shift.
You may notice that it is harder to shift when
the vehicle is cold. After the vehicle warms
up the shifting will return to normal.
While in Four-Wheel High or Four-Wheel-Drive
Low you may experience reduced fuel
economy.
Avoid driving in Four-Wheel Drive on clean,
dry pavement. It may cause your tires to
wear faster, and make the transfer case harder
to shift and run noisier.
If the transfer case shifter is in the NEUTRAL
position and you have difficulty reaching the
selected transfer case mode, with the
engine running, shift the transmission
momentarily to drive and then back to
NEUTRAL. This will realign the gear teeth in
the transfer case and allow you to complete
the shift.
Shifting from Two-Wheel-Drive High to
Four-Wheel-Drive High

Shifts between Two-Wheel-Drive High and
Four-Wheel-Drive High can be made at
any vehicle speed.
Shift the transfer case lever in one continuous
motion into either the Four-Wheel-Drive High
or Two-Wheel-Drive High position.
In extremely cold weather, it may be
necessary to slow or stop the vehicle to shift
into Four-wheel-Drive High until your
vehicle has warmed up.
While in Four-Wheel-Drive High, your vehicle
can be driven at any posted legal speed
limit.
152

Shifting In or Out of Four-Wheel-Drive Low
Notice:Shifting the transfer case into
Four-Wheel-Drive Low 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 Four-Wheel-Drive
Low while the vehicle is moving faster than
3 mph (5 km/h).
Shifting into Four-Wheel-Drive Low should be done,
if possible, with the vehicle at a slight roll, 3 mph
(5 km/h) or less.
Shift the transmission into NEUTRAL (N).
{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. See
Parking Brake on page 164.
Shifting into Four-Wheel-Drive Low with
the vehicle at a stop may be more difficult.
You may be unable to complete the shift to
Four-Wheel-Drive Low, and will end up in
NEUTRAL. This is normal, and is a function of
the gear teeth aligning in your transfer case.
When this happens, make sure the engine is
on, shift your transmission momentarily to
drive and back to NEUTRAL, and then
complete the shift.
Shift the transfer case shift lever in one
continuous motion into the Four-Wheel-Drive
Low position.
When Four-Wheel-Drive Low do not drive
faster than 45 mph. This will reduce wear and
extend the life of your transfer case.
Shifting In or Out of NEUTRAL
1. With the vehicle running and the engine at an
idle set the parking brake.
2. Place the transmission into NEUTRAL (N).
Shift the transfer case in one continuous motion
into or out of the NEUTRAL position.
153

4n(Four-Wheel-Drive Low):This setting also
engages the front axle and delivers extra
torque. You may never need this setting. It sends
maximum power to all four wheels. You might
choose Four-Wheel-Drive Low while driving
off-road in deep sand, deep mud, deep snow, and
while climbing or descending steep hills.
StabiliTrak
®will not engage in this mode.
{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 164.
N (NEUTRAL):Shift the vehicle’s transfer case to
NEUTRAL only when towing your vehicle. See
Recreational Vehicle Towing on page 442or
Towing Your Vehicle on page 441for more
information.If the SERVICE 4–Wheel Drive message stays on,
you should take your vehicle to your dealer for
service. See “Service 4–Wheel Drive message”
underDIC Warnings and Messages on page 281.
Shifting Into Two-Wheel-Drive High
Turn the knob to the Two-Wheel-Drive High
position. This can be done at any speed, except
when shifting from Four-Wheel-Drive Low.
See Shifting Out of Four-Wheel-Drive Low for
more information.
Shifting Into Four-Wheel Drive Low
When Four-Wheel-Drive Low is engaged, vehicle
speed should be kept below 45 mph. Extended
high-speed operation in Four-Wheel-Drive Low may
damage or shorten the life of the drivetrain.
To shift to the Four-Wheel-Drive Low position,
the ignition must be in RUN and the vehicle must be
stopped or moving less than 3 mph (5 km/h) with
the transmission in NEUTRAL (N). The preferred
method for shifting into Four-Wheel-Drive Low
is to have your vehicle moving 1 to 2 mph
(1.6 to 3.2 km/h). Turn the knob to the
Four-Wheel-Drive Low position.
155

You must wait for the Four-Wheel-Drive Low
indicator light to stop ashing and remain on before
shifting your transmission in gear.
Notice:Shifting the transmission into gear
before the requested mode indicator light has
stopped ashing could damage the transfer
case. To help avoid damaging your vehicle,
always wait for the mode indicator lights
to stop ashing before shifting the
transmission into gear.
It is typical for your vehicle to exhibit signicant
engagement noise and bump when shifting
between Four-Wheel-Drive Low and
Four-Wheel-Drive High ranges or from NEUTRAL
with the engine running.
If the knob is turned to the Four-Wheel-Drive Low
position when your vehicle is in gear and/or
moving, the Four-Wheel-Drive Low indicator light
will ash for 30 seconds and not complete the
shift unless your vehicle is moving less than 3 mph
(5 km/h) and the transmission is in NEUTRAL (N).
After 30 seconds the transfer case will shift to
Four-Wheel-Drive High mode.Shifting Out of Four-Wheel-Drive Low
To shift from Four-Wheel-Drive Low to
Four-Wheel-Drive High, or Two-Wheel-Drive High,
your vehicle must be stopped or moving less
than 3 mph (5 km/h) with the transmission
in NEUTRAL (N) and the ignition in RUN. The
preferred method for shifting out of
Four-Wheel-Drive Low is to have your vehicle
moving 1 to 2 mph (1.6 to 3.2 km/h). Turn the knob
to the Four-Wheel-Drive High, or Two-Wheel-Drive
High position. You must wait for the
Four-Wheel-Drive High, or Two-Wheel-Drive High
indicator light to stop ashing and remain on
before shifting the transmission into gear.
Notice:Shifting the transmission into gear
before the requested mode indicator light has
stopped ashing could damage the transfer
case. To help avoid damaging your vehicle,
always wait for the mode indicator lights
to stop ashing before shifting the
transmission into gear.
It is typical for your vehicle to exhibit signicant
engagement noise and bump when shifting
between Four-Wheel-Drive Low and
Four-Wheel-Drive High ranges or from NEUTRAL
with the engine running.
156

If the knob is turned to the Four-Wheel-Drive High,
or Two-Wheel-Drive High switch position when
your vehicle is in gear and/or moving, the
Four-Wheel-Drive High, or Two-Wheel-Drive High
indicator light will ash for 30 seconds but will
not complete the shift unless your vehicle is
moving less than 3 mph (5 km/h) and the
transmission is in NEUTRAL (N).
Shifting into NEUTRAL
To shift the transfer case to NEUTRAL do the
following:
1. Make sure the vehicle is parked so that it will
not roll.
2. Set the parking brake and press and hold the
regular brake pedal. SeeParking Brake on
page 164for more information.
3. Start the vehicle or turn the ignition to RUN.
4. Shift the transmission to NEUTRAL (N).5. Shift the transfer case to
Two-Wheel-Drive High.
6. Turn the transfer case dial clockwise to
NEUTRAL till it stops and hold it for
10 seconds. Then slowly release the dial to
the four low position. The NEUTRAL light will
come on when the transfer case shift to
NEUTRAL is complete.
7. If the engine is running, verify that the
transmission is in NEUTRAL (N) by shifting the
transmission to REVERSE (R) for one second,
then shift the transmission to DRIVE (D) for
one second.
8. Turn the ignition to ACCESSORY, which will
turn the engine off.
9. Place the transmission shift lever in PARK (P).
10. Release the parking brake prior to moving
the vehicle.
11. Turn the ignition to LOCK.
157