CHEVROLET SILVERADO 2009 2.G Owners Manual

The vehicle has a shift stabilization feature that adjusts
the transmission shifting to the current driving
conditions in order to reduce rapid upshifts and
downshifts. This shift stabilization feature is designed to
determine, before making an upshift, if the engine is
able to maintain vehicle speed by analyzing things such
as vehicle speed, throttle position, and vehicle load.
If the shift stabilization feature determines that a current
vehicle speed cannot be maintained, the transmission
does not upshift and instead holds the current gear.
In some cases, this could appear to be a delayed shift,
however the transmission is operating normally.
The transmission uses adaptive shift controls.
Adaptive shift controls continually compares key shift
parameters to pre-programmed ideal shifts stored in the
transmissions computer. The transmission constantly
makes adjustments to improve vehicle performance
according to how the vehicle is being used, such as with
a heavy load or when temperature changes. During
this adaptive shift control process, shifting might
feel different as the transmission determines the best
settings.
When temperatures are very cold, the Allison
Transmission
®and Hydra-Matic®6-Speed
transmission’s gear shifting could be delayed providing
more stable shifts until the engine warms up. Shifts
could be more noticeable with a cold transmission. This
difference in shifting is normal.M (Manual Mode):This position is available on
vehicles with the Allison Transmission
®or Hydra-Matic®
6-Speed transmission. It lets drivers select the range
of gears appropriate for current driving conditions. If the
vehicle has this feature, see Range Select Mode
(Allison Transmission
®or Hydra-Matic®6-Speed
transmission) later in this section.
3 (Third):This position is also used for normal driving.
It reduces vehicle speed more than D (Drive) without
using the brakes. You might choose 3 (Third) instead of
D (Drive) when driving on hilly, winding roads, when
towing a trailer, so there is less shifting between gears
and when going down a steep hill.
2 (Second):This position reduces vehicle speed even
more than 3 (Third) without using the brakes. You
can use 2 (Second) on hills. It can help control vehicle
speed as you go down steep mountain roads, but
then you would also want to use the brakes off and on.
If you manually select 2 (Second) in an automatic
transmission, the transmission will start in second gear.
You can use this feature for reducing the speed of
the rear wheels when you are trying to start the vehicle
from a stop on slippery road surfaces.
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1 (First):For the Hydra-Matic®4-Speed transmission
this position reduces vehicle speed even more than
2 (Second) without using the brakes. You can use it on
very steep hills, or in deep snow or mud. If the shift
lever is put in 1 (First) while the vehicle is moving
forward, the transmission does not shift into rst gear
until the vehicle is going slowly enough.
For an Allison Transmission
®or Hydra-Matic®6-Speed
transmission, this position reduces vehicle speed
without using the brakes. You can use it for
major/severe downgrades and off-road driving where
the vehicle would otherwise accelerate due to steepness
of grade. When you shift to 1 (First) it provides the
lowest gear appropriate to current road speed and
continues to downshift as the vehicle slows, eventually
downshifting to 1 (First) gear.
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 the vehicle warranty. If you
are stuck, do not spin the tires. When stopping on a
hill, use the brakes to hold the vehicle in place.
Range Selection Mode (Allison®or
Hydra-Matic®6-Speed Transmission)
The vehicle may have a Range Selection Mode. The
Range Selection Mode helps control the vehicle’s
transmission and vehicle speed while driving down hill
or towing a trailer by letting you select a desired range of
gears.
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To use this feature, do the following:
1. Move the shift lever to M (Manual Mode).
2. Press the plus/minus buttons, located on the
steering column shift lever, to select the desired
range of gears for current driving conditions.
When M (Manual Mode) is selected a number displays
next to the M, indicating the current gear.
This number is the highest gear that can be used.
However, the vehicle can automatically shift to lower
gears as it adjusts to driving conditions. This means that
all gears below that number are available. When
5 (Fifth) is selected, 1 (First) through 5 (Fifth) gears are
automatically shifted by the vehicle, but 6 (Sixth)
cannot be used until the plus/minus button located on
the steering column lever is used to change to the gear.
Grade Braking is not available when Range Selection
Mode is active. SeeTow/Haul Mode on page 2-34.While using Range Selection Mode, 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 the vehicle 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®,orthe
Hydra-Matic®6-Speed Automatic Transmission, it has a
Low Traction Mode that can 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 Range Selection Mode.
This will limit torque to the wheels after it detects wheel
slip, preventing the tires from spinning.
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Tow/Haul Mode
Vehicles with an automatic transmission have 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.
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 3-51for more
information.Also see Tow Haul Mode underTowing a Trailer on
page 4-51for more information.
Tow/Haul Mode (Allison Transmission®
or Hydra-Matic®6-Speed Automatic
Transmission)
Vehicles with an Allison or Hydra-Matic®6-speed
automatic transmission®have 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 3-51for more
information.
Also see “Tow Haul Mode” underTowing a Trailer on
page 4-51for 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 and
Automatic Transmission Operation on page 2-28for
more information on the Range Selection 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 thevehicle. 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.
Also seeTowing a Trailer on page 4-51for more
information.
Cruise Grade Braking (Allison
Transmission®or Hydra-Matic®
6-Speed Automatic Transmission)
Cruise Grade Braking assists when driving on a downhill
grade. It maintains vehicle speed by automatically
implementing a shift schedule that uses the engine and
the transmission to slow the vehicle. Cruise Grade
Braking operates while Cruise Control is engaged in
Tow/Haul mode to assist in maintaining vehicle speed
under loaded vehicle conditions. It utilizes vehicle
acceleration and deviation from desired speed to
determine the correct gear for the operating condition. If
vehicle speed is above the desired speed the
transmission will downshift to slow the vehicle. If vehicle
speed is near or below desired speed the trans will
upshift, allowing vehicle speed to increase.
While in the Range Select Mode (RSM) mode, cruise
grade braking is not available.
SeeAutomatic Transmission Operation on page 2-28.
2-35

Four-Wheel Drive
If the vehicle has Four-Wheel Drive, you can send the
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 following before using Four-Wheel Drive. See the
appropriate text for the transfer case in the vehicle.
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.
While driving on clean dry pavement and during tight
turns, you may experience vibration in the steering
system.
If the vehicle has StabiliTrak
®, shifting into
Four-Wheel-Drive Low will turn Traction Control and
StabiliTrak
®off. SeeStabiliTrak®System on page 4-6.
Front Axle
The front axle engages and disengages automatically
when you shift the transfer case. Some delay for
the axle to engage or disengage is normal.
Manual Transfer Case
The transfer case shift lever is on the oor to the right
of the driver. Use this lever to shift into and out of
Four-Wheel Drive.
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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 3-51.
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 4-46
Towing Your Vehicle on page 4-45Notice:Driving on clean, dry pavement in
four-wheel drive for an extended period of time can
cause premature wear on the 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.
If the vehicle has StabiliTrak
®, shifting into
Four-Wheel-Drive Low will turn Traction Control and
StabiliTrak
®off. SeeStabiliTrak®System on page 4-6.
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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 into
N (Neutral).
{CAUTION:
Shifting the transfer case to Neutral can cause the
vehicle to roll even if the transmission is in
P (Park). 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 2-50.N (Neutral):Shift to this setting only when the vehicle
needs to be towed. SeeRecreational Vehicle Towing
on page 4-46orTowing Your Vehicle on page 4-45.
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.
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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,
make the transfer case harder to shift, and run
noisier.
If the transfer case shifter is in the N (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 N (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 the vehicle has
warmed up.
While in Four-Wheel-Drive High, the vehicle can
be driven at any posted legal speed limit.
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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 N (Neutral).
{CAUTION:
Shifting the transfer case to Neutral can cause the
vehicle to roll even if the transmission is in
P (Park). 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 2-50.
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 the transfer case will end up in N (Neutral). This
is normal, and is a function of the gear teeth
aligning in the transfer case. When this happens,
make sure the engine is on, shift the transmission
momentarily to D (Drive) and back to N (Neutral),
and then complete the transfer case 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 N (Neutral).
Shift the transfer case in one continuous motion into or
out of the N (Neutral) position.
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