torque GMC YUKON 2009 Owner's Manual
[x] Cancel search | Manufacturer: GMC, Model Year: 2009, Model line: YUKON, Model: GMC YUKON 2009Pages: 576, PDF Size: 3.06 MB
Page 136 of 576

See “Range Selection Mode” later in this section.
P (Park):This position locks the rear wheels. It is the
best position to use when starting the engine because the
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 P (Park). See
Torque Lock (Automatic Transmission) underShifting
Into Park on page 2-44for more information.
{CAUTION:
It is dangerous to get out of the vehicle if the shift
lever is not fully in P (Park) with the parking brake
rmly set. The vehicle can roll.
CAUTION: (Continued)
CAUTION: (Continued)
Do not leave the vehicle when the engine is
running unless you have to. If you have left the
engine running, the vehicle can move suddenly.
You or others could be injured. To be sure the
vehicle will not move, even when you are on fairly
level ground, always set the parking brake and
move the shift lever to P (Park). SeeShifting Into
Park on page 2-44. If you are pulling a trailer, see
Towing a Trailer on page 4-52.
{CAUTION:
If you have Four-Wheel Drive, the vehicle will
be free to roll — even if the shift lever is in
P (Park) — if the transfer case is in Neutral. So,
be sure the transfer case is in a drive gear,
Two-Wheel Drive High or Four-Wheel Drive High
or Four-Wheel Drive Low — not in Neutral. See
Shifting Into Park on page 2-44. Hevay Duty 6-Speed Automatic Transmission
Shown (Light Duty Similar)
2-30
Page 140 of 576

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 2-35
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 the vehicle has the Hydra-Matic®6-Speed Automatic
Transmission, it has a Low Traction Mode that assists
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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Page 142 of 576

Grade Braking (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 2-29for 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 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.
Also seeTowing a Trailer on page 4-52for more
information.
Cruise Grade Braking (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 2-29.
2-36
Page 144 of 576

2m(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.
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.
4
m(Four-Wheel Drive High):Use the four-wheel high
position when you need extra traction, such as 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 this setting. 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.
The vehicle has StabiliTrak
®. Shifting into
Four-Wheel-Drive Low will turn Traction Control and
StabiliTrak
®off. SeeStabiliTrak®System on page 4-6.
{CAUTION:
Shifting the transfer case to N (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 N (Neutral). See
Parking Brake on page 2-42.
N (Neutral):Shift the vehicle’s transfer case to
N (Neutral) only when towing the vehicle. See
Recreational Vehicle Towing on page 4-44orTowing
Your Vehicle on page 4-44for more information.
If the SERVICE 4 WHEEL DRIVE message stays on,
you should take the vehicle to your dealer/retailer
for service. See “SERVICE 4 WHEEL DRIVE message”
underDIC Warnings and Messages on page 3-64.
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