2008 CHEVROLET TAHOE automatic transmission

Automatic Release Fold and
Tumble Feature
The transmission must be in PARK (P) for this feature
to work.
Folding and Tumbling the Seat(s)
{CAUTION:
Automatically folding and tumbling the seat
when someone is sitting in the seat, could cause
injury to the person sitting there. Always make
sure there is no one sitting in the seat before
pressing the automatic seat release button.
To fold and tumble the seat, do the following:
1. Make sure that there is nothing under, in front of,
or on the seat.
Notice:Folding a rear seat with the safety belts
still fastened may cause damage to the seat or
the safety belts. Always unbuckle the safety belts
and return them to their normal stowed position
before folding a rear seat.2. From the front seats,
press one of the
automatic seat release
buttons located on
the overhead console.
When accessing the third row seats, if your vehicle
has them, from the outside of the vehicle, press
the button on the panel behind either rear door.
One press of the button automatically folds
the seatback at and tumbles the seat forward.
There will be a slight delay between the folding of
the seatback and the tumbling of the seat. Overhead Console
Buttons shown,
Panel Button similar
1-16

Folding and Tumbling the Seat(s) from
the Third Row Seats
{CAUTION:
Using the third row seating position while the
second row is folded, or folded and tumbled,
could cause injury in a sudden stop or crash.
Be sure to return the seat to the passenger
seating position. Push and pull on the seat
to make sure it is locked into place.
To fold and tumble the seat from the third row seats,
if your vehicle has them, do the following:
1. Make sure that there is nothing under, in front of,
or on the seat.
Notice:Folding a rear seat with the safety belts
still fastened may cause damage to the seat or
the safety belts. Always unbuckle the safety belts
and return them to their normal stowed position
before folding a rear seat.2. Lift the lever, located
on the bottom rear of
the second row seat
on the inboard side,
to release the seatback.
The seatback will fold
forward.
3. Lift the lever again to release the rear of the seat
from the oor. The seat will tumble forward.
Automatic Release Fold and
Tumble Feature
The transmission must be in PARK (P) for this
feature to work.
1-22

Keys...............................................................2-3
Remote Keyless Entry (RKE) System................2-4
Remote Keyless Entry (RKE) System
Operation...................................................2-5
Remote Vehicle Start......................................2-8
Doors and Locks............................................2-10
Door Locks..................................................2-10
Power Door Locks........................................2-10
Delayed Locking...........................................2-11
Programmable Automatic Door Locks..............2-11
Rear Door Security Locks..............................2-11
Lockout Protection........................................2-12
Liftgate/Liftglass............................................2-12
Power Liftgate..............................................2-14
Power Running Boards..................................2-17
Windows........................................................2-18
Power Windows............................................2-19
Sun Visors...................................................2-20
Theft-Deterrent Systems..................................2-20
Content Theft-Deterrent.................................2-21
PASS-Key
®III+ Electronic Immobilizer.............2-22
PASS-Key®III+ Electronic Immobilizer
Operation.................................................2-23Starting and Operating Your Vehicle................2-24
New Vehicle Break-In....................................2-24
Ignition Positions..........................................2-25
Retained Accessory Power (RAP)...................2-26
Starting the Engine.......................................2-26
Adjustable Throttle and Brake Pedal................2-28
Engine Coolant Heater..................................2-28
Active Fuel Management™.............................2-29
Automatic Transmission Operation...................2-30
Tow/Haul Mode............................................2-36
Four-Wheel Drive..........................................2-36
Parking Brake..............................................2-42
Shifting Into Park..........................................2-43
Shifting Out of Park......................................2-45
Parking Over Things That Burn.......................2-45
Engine Exhaust............................................2-46
Running the Vehicle While Parked..................2-46
Mirrors...........................................................2-47
Automatic Dimming Rearview Mirror with
OnStar
®, Compass and Temperature
Display....................................................2-47
Automatic Dimming Rearview Mirror with
Compass and Temperature Display..............2-49
Section 2 Features and Controls
2-1

Automatic Transmission Operation
If your vehicle is a Two-mode Hybrid, see the Two-mode
Hybrid manual for more information.
If your vehicle is has an automatic transmission,
it has an electronic shift position indicator within the
instrument panel cluster. This display comes on when
the ignition key is turned to the ON/RUN position.
There are several different positions for the shift lever.
See “Range Selection Mode” later in this section.
PARK (P):This position locks your rear wheels. It is
the best position to use when you start the engine
because your vehicle cannot move easily. When parked
on a hill, especially when the vehicle has a heavy
load, you might notice an increase in the effort to shift
out of Park. See Torque Lock (Automatic Transmission)
underShifting Into Park on page 2-43for more
information.
Hydra-Matic
®4-Speed
Automatic Transmission
Allison Transmission®or Hydra-Matic®6-Speed
Automatic Transmission
2-30

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.
Your vehicle’s 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.MANUAL MODE (M):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 your
vehicle has this feature, see Range Select Mode
(Allison Transmission
®or Hydra-Matic®6-Speed
transmission) later in this section.
THIRD (3):This position is also used for normal driving.
It reduces vehicle speed more than DRIVE (D) without
using the brakes. You might choose THIRD (3)
instead of DRIVE (D) when driving on hilly, winding
roads, when towing a trailer, so there is less shifting
between gears and when going down a steep hill.
SECOND (2):This position reduces vehicle speed even
more than THIRD (3) without using your brakes. You can
use SECOND (2) on hills. It can help control your 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 SECOND (2) 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 your vehicle from
a stop on slippery road surfaces.
2-33

To use this feature, do the following:
1. Move the shift lever to the MANUAL MODE (M).
2. Press the plus/minus buttons, located on the
steering column shift lever, to select the desired
range of gears for your current driving conditions.
When MANUAL MODE (M) is selected a number
displays next to the M, indicating the current gear.
This number is the highest gear that can be used.
However, your vehicle can automatically shift to lower
gears as it adjusts to driving conditions. This means that
all gears below that number are available. When
FIFTH (5) is selected, FIRST (1) through FIFTH (5)
gears are automatically shifted by the vehicle, but
SIXTH (6) 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 the Range
Selection Mode is active. SeeTow/Haul Mode on
page 2-36While 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®,orthe
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.
2-35

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.
Automatic Transfer Case
The transfer case knob is
located to the left of the
instrument panel cluster.
Your vehicle has Four Wheel Drive with StabiliTrak
®.
For information on StabiliTrak®, seeStabiliTrak®System
on page 4-6.
Use this dial to shift into and out of four-wheel drive.You can choose among ve driving settings:
Indicator lights in the switches show you which setting
you are in. 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 in for service. An indicator light will ash
while shifting. Fast ashing means the conditions
were not met to make the desired shift, typically the
vehicle was going too fast, the automatic transmission
was not in neutral. 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.
2
m(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.
AUTO (Automatic Four-Wheel Drive):This setting is
ideal for use when road surface traction conditions
are variable. When driving your vehicle in AUTO, 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.
2-37

Shifting Into Four-Wheel Drive High or
AUTO (Automatic Four-Wheel Drive)
Turn the knob to the Four-Wheel High or AUTO position.
This can be done at any speed, except when shifting
from Four-Wheel Drive Low. The indicator light will ash
while shifting. It will remain on when the shift is
completed.
Shifting Into Two-Wheel Drive High
Turn the knob to the Two-Wheel 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 later in this
section for more information.
Shifting Into Four-Wheel Drive Low
When Four-Wheel Low is engaged, vehicle speed
should be kept below 45 mph. Extended high-speed
operation in 4L may damage or shorten the life of
the drivetrain.
To shift to the Four-Wheel Drive Low position, the
ignition must be in ON/RUN and the vehicle must be
stopped or moving less than 3 mph (5 km/h) with
the transmission in NEUTRAL (N). The preferred methodfor 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. 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 Four-Wheel Drive Low indicator light has stopped
ashing could damage the transfer case. To help
avoid damaging your vehicle, always wait for the
Four-Wheel Drive Low indicator light to stop ashing
before shifting the transmission into gear.
The vehicle may have signicant engagement noise and
bump when shifting between Four-Wheel Drive Low
and Four-Wheel Drive High ranges or from NEUTRAL
while the engine is 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.
2-39