2011 GMC YUKON XL brakes

Black plate (3,1)GMC Yukon/Yukon XL Owner Manual - 2011
Driving and Operating 9-3
Death and injury associated with
drinking and driving is a global
tragedy.
Alcohol affects four things that
anyone needs to drive a vehicle:
judgment, muscular coordination,
vision, and attentiveness.
Police records show that
almost 40 percent of all motor
vehicle-related deaths involve
alcohol. In most cases, these
deaths are the result of someone
who was drinking and driving.
In recent years, more than
17,000 annual motor vehicle-related
deaths have been associated
with the use of alcohol, with about
250,000 people injured.For persons under 21, it is against
the law in every U.S. state to drink
alcohol. There are good medical,
psychological, and developmental
reasons for these laws.
The obvious way to eliminate the
leading highway safety problem is
for people never to drink alcohol
and then drive.
Medical research shows that
alcohol in a person's system
can make crash injuries worse,
especially injuries to the brain,
spinal cord, or heart. This means
that when anyone who has
been drinking
—driver or
passenger —is in a crash, that
person's chance of being killed or
permanently disabled is higher than
if the person had not been drinking.Control of a Vehicle
The following three systems
help to control the vehicle while
driving —brakes, steering, and
accelerator. At times, as when
driving on snow or ice, it is easy to
ask more of those control systems
than the tires and road can provide.
Meaning, you can lose control of the
vehicle. See StabiliTrak
®System on
page 9‑52.
Adding non‐dealer accessories can
affect vehicle performance. See
Accessories and Modifications on
page 10‑3.

Black plate (4,1)GMC Yukon/Yukon XL Owner Manual - 2011
9-4 Driving and Operating
Braking
SeeBrake System Warning Light on
page 5‑23.
Braking action involves perception
time and reaction time. Deciding
to push the brake pedal is
perception time. Actually doing
it is reaction time.
Average reaction time is about
three‐fourths of a second. But
that is only an average. It might be
less with one driver and as long as
two or three seconds or more with
another. Age, physical condition,
alertness, coordination, and
eyesight all play a part. So do
alcohol, drugs, and frustration.
But even in three‐fourths of
a second, a vehicle moving at
100 km/h (60 mph) travels 20 m
(66 ft). That could be a lot of
distance in an emergency, so
keeping enough space between the
vehicle and others is important. And, of course, actual stopping
distances vary greatly with the
surface of the road, whether it is
pavement or gravel; the condition
of the road, whether it is wet, dry,
or icy; tire tread; the condition of the
brakes; the weight of the vehicle;
and the amount of brake force
applied.
Avoid needless heavy
braking. Some people drive in
spurts
—heavy acceleration
followed by heavy braking —rather
than keeping pace with traffic. This
is a mistake. The brakes might not
have time to cool between hard
stops. The brakes will wear out
much faster with a lot of heavy
braking. Keeping pace with the
traffic and allowing realistic
following distances eliminates
a lot of unnecessary braking.
That means better braking and
longer brake life. If the engine ever stops while the
vehicle is being driven, brake
normally but do not pump the
brakes. If the brakes are pumped,
the pedal could get harder to push
down. If the engine stops, there will
still be some power brake assist but
it will be used when the brake is
applied. Once the power assist is
used up, it can take longer to stop
and the brake pedal will be harder
to push.
Adding non‐dealer accessories can
affect vehicle performance. See
Accessories and Modifications on
page 10‑3.

Black plate (5,1)GMC Yukon/Yukon XL Owner Manual - 2011
Driving and Operating 9-5
Steering
Power Steering
If the vehicle is a hybrid, see
the hybrid supplement for more
information.
If power steering assist is lost
because the engine stops or the
power steering system is not
functioning, the vehicle can be
steered but it will take more effort.
Steering Tips
It is important to take curves at a
reasonable speed.
Traction in a curve depends on the
condition of the tires and the road
surface, the angle at which the
curve is banked, and vehicle speed.
While in a curve, speed is the one
factor that can be controlled.
If there is a need to reduce speed,
do it before entering the curve, while
the front wheels are straight.Try to adjust the speed so you can
drive through the curve. Maintain a
reasonable, steady speed. Wait to
accelerate until out of the curve,
and then accelerate gently into the
straightaway.
Steering in Emergencies
There are times when steering can
be more effective than braking. For
example, you come over a hill and
find a truck stopped in your lane,
or a car suddenly pulls out from
nowhere, or a child darts out from
between parked cars and stops right
in front of you. These problems can
be avoided by braking
—if you can
stop in time. But sometimes you
cannot stop in time because there
is no room. That is the time for
evasive action —steering around
the problem.
The vehicle can perform very well
in emergencies like these. First,
apply the brakes. See Braking on
page 9‑4. It is better to remove
as much speed as possible from a collision. Then steer around
the problem, to the left or right
depending on the space available.
An emergency like this requires
close attention and a quick decision.
If holding the steering wheel at the
recommended 9 and 3 o'clock
positions, it can be turned a full
180 degrees very quickly without
removing either hand. But you have
to act fast, steer quickly, and just as
quickly straighten the wheel once
you have avoided the object.

Black plate (6,1)GMC Yukon/Yukon XL Owner Manual - 2011
9-6 Driving and Operating
The fact that such emergency
situations are always possible is a
good reason to practice defensive
driving at all times and wear safety
belts properly.
Off-Road Recovery
The vehicle's right wheels can drop
off the edge of a road onto the
shoulder while driving.
If the level of the shoulder is
only slightly below the pavement,
recovery should be fairly easy. Ease
off the accelerator and then, if thereis nothing in the way, steer so that
the vehicle straddles the edge of
the pavement. Turn the steering
wheel 8 to 13 cm (3 to 5 in), about
one-eighth turn, until the right front
tire contacts the pavement edge.
Then turn the steering wheel to go
straight down the roadway.
Loss of Control
Let us review what driving experts
say about what happens when the
three control systems
—brakes,
steering, and acceleration —do not
have enough friction where the tires
meet the road to do what the driver
has asked.
In any emergency, do not give up.
Keep trying to steer and constantly
seek an escape route or area of
less danger.
Skidding
In a skid, a driver can lose control of
the vehicle. Defensive drivers avoid
most skids by taking reasonable
care suited to existing conditions,
and by not overdriving those
conditions. But skids are always
possible.
The three types of skids correspond
to the vehicle's three control
systems. In the braking skid, the
wheels are not rolling. In the
steering or cornering skid, too much
speed or steering in a curve causes
tires to slip and lose cornering force.
And in the acceleration skid, too
much throttle causes the driving
wheels to spin.
If the vehicle starts to slide, ease
your foot off the accelerator pedal
and quickly steer the way you
want the vehicle to go. If you start
steering quickly enough, the vehicle
may straighten out. Always be ready
for a second skid if it occurs.

Black plate (7,1)GMC Yukon/Yukon XL Owner Manual - 2011
Driving and Operating 9-7
Of course, traction is reduced when
water, snow, ice, gravel, or other
material is on the road. For safety,
slow down and adjust your driving to
these conditions. It is important to
slow down on slippery surfaces
because stopping distance is longer
and vehicle control more limited.
While driving on a surface with
reduced traction, try to avoid
sudden steering, acceleration,
or braking, including reducing
vehicle speed by shifting to a lower
gear. Any sudden changes could
cause the tires to slide. You might
not realize the surface is slippery
until the vehicle is skidding. Learn to
recognize warning clues—such as
enough water, ice, or packed snow
on the road to make a mirrored
surface —and slow down when you
have any doubt.
Remember: Antilock brakes help
avoid only the braking skid.Off-Road Driving
Vehicles with four-wheel drive
can be used for off-road driving.
Vehicles without four-wheel drive
and vehicles with 20‐inch tire/wheel
assemblies should not be driven
off-road except on a level, solid
surface.
The airbag system is designed to
work properly under a wide range of
conditions, including off‐road usage.
Always wear your safety belt and
observe safe driving speeds,
especially on rough terrain.
Drinking and driving can be very
dangerous on any road and this is
certainly true for off-road driving.
At the very time you need special
alertness and driving skills, your
reflexes, perceptions, and judgment
can be affected by even a small
amount of alcohol. You could have a
serious —or even fatal —accident
if you drink and drive or ride with a
driver who has been drinking. Off-roading can be great fun but has
some definite hazards. The greatest
of these is the terrain itself. When
off-road driving, traffic lanes are not
marked, curves are not banked, and
there are no road signs. Surfaces
can be slippery, rough, uphill,
or downhill.
Avoid sharp turns and abrupt
maneuvers. Failure to operate the
vehicle correctly off‐road could
result in loss of vehicle control or
vehicle rollover.
Off-roading involves some new
skills. That is why it is very
important that you read these
driving tips and suggestions to
help make off-road driving safer
and more enjoyable.

Black plate (14,1)GMC Yukon/Yukon XL Owner Manual - 2011
9-14 Driving and Operating
Exit on the uphill side and stay clear
of the path the vehicle would take if
it rolled downhill. If the vehicle has
a transfer case with a N (Neutral)
position, do not shift the transfer
case to Neutral when you leave the
vehicle. Leave it in some gear.
{WARNING
If the vehicle has the two‐speed
automatic transfer case, shifting
the transfer case to Neutral can
cause your vehicle to roll even if
the transmission is in P (Park).
This is because the Neutral
position on the transfer case
overrides the transmission. You
or someone else could be injured.
If you are going to leave your
vehicle, set the parking brake
and shift the transmission to
P (Park). But, if the vehicle has
a two‐speed automatic transfer
case, do not shift the transfer
case to Neutral.
Driving Downhill
When off-roading takes you
downhill, consider:
.How steep is the downhill? Will
I be able to maintain vehicle
control?
.What is the surface like?
Smooth? Rough? Slippery?
Hard-packed dirt? Gravel?
.Are there hidden surface
obstacles? Ruts? Logs?
Boulders?
.What is at the bottom of the hill?
Is there a hidden creek bank or
even a river bottom with large
rocks?
If you decide you can go down a
hill safely, try to keep the vehicle
headed straight down. Use a low
gear so engine drag can help the
brakes so they do not have to do all
the work. Descend slowly, keeping
the vehicle under control at all
times.
{WARNING
Heavy braking when going down
a hill can cause your brakes to
overheat and fade. This could
cause loss of control and a
serious accident. Apply the
brakes lightly when descending a
hill and use a low gear to keep
vehicle speed under control.
Things not to do when driving down
a hill:
.When driving downhill, avoid
turns that take you across the
incline of the hill. A hill that is not
too steep to drive down might be
too steep to drive across. The
vehicle could roll over.
.Never go downhill with the
transmission in N (Neutral),
called free-wheeling. The brakes
will have to do all the work and
could overheat and fade.

Black plate (15,1)GMC Yukon/Yukon XL Owner Manual - 2011
Driving and Operating 9-15
Vehicles are much more likely to
stall when going uphill, but if it
happens when going downhill:
1. Stop the vehicle by applying theregular brakes and apply the
parking brake.
2. Shift to P (Park) and, while still braking, restart the engine.
3. Shift back to a low gear, release the parking brake, and drive
straight down.
4. If the engine will not start, get out and get help.
Driving Across an Incline
An off-road trail will probably go
across the incline of a hill. To decide
whether to try to drive across the
incline, consider the following:
{WARNING
Driving across an incline that is
too steep will make your vehicle
roll over. You could be seriously
(Continued)
WARNING (Continued)
injured or killed. If you have any
doubt about the steepness of the
incline, do not drive across it.
Find another route instead.
.A hill that can be driven straight
up or down might be too steep
to drive across. When going
straight up or down a hill, the
length of the wheel base —the
distance from the front wheels to
the rear wheels —reduces the
likelihood the vehicle will tumble
end over end. But when driving
across an incline, the narrower
track width —the distance
between the left and right
wheels —might not prevent the
vehicle from tilting and rolling
over. Driving across an incline
puts more weight on the downhill
wheels which could cause a
downhill slide or a rollover.
.Surface conditions can be a
problem. Loose gravel, muddy
spots, or even wet grass can
cause the tires to slip sideways,
downhill. If the vehicle slips
sideways, it can hit something
that will trip it —a rock, a rut,
etc. —and roll over.
.Hidden obstacles can make the
steepness of the incline even
worse. If you drive across a rock
with the uphill wheels, or if the
downhill wheels drop into a rut
or depression, the vehicle can tilt
even more.
For these reasons, carefully
consider whether to try to drive
across an incline. Just because the
trail goes across the incline does
not mean you have to drive it. The
last vehicle to try it might have
rolled over.

Black plate (17,1)GMC Yukon/Yukon XL Owner Manual - 2011
Driving and Operating 9-17
Driving in Water
{WARNING
Driving through rushing water can
be dangerous. Deep water can
sweep your vehicle downstream
and you and your passengers
could drown. If it is only shallow
water, it can still wash away the
ground from under your tires, and
you could lose traction and roll
the vehicle over. Do not drive
through rushing water.
Heavy rain can mean flash flooding,
and flood waters demand extreme
caution. Find out how deep the water is
before driving through it. Do not try
it if it is deep enough to cover the
wheel hubs, axles, or exhaust
pipe
—you probably will not get
through. Deep water can damage
the axle and other vehicle parts.
If the water is not too deep, drive
slowly through it. At faster speeds,
water splashes on the ignition
system and the vehicle can stall.
Stalling can also occur if you get the
tailpipe under water. If the tailpipe is
under water, you will never be able
to start the engine. When going
through water, remember that when
the brakes get wet, it might take
longer to stop. See Driving on Wet
Roads on page 9‑18.
After Off-Road Driving
Remove any brush or debris that
has collected on the underbody,
chassis, or under the hood. These
accumulations can be a fire hazard.
After operation in mud or sand,
have the brake linings cleaned and
checked. These substances can
cause glazing and uneven braking.
Check the body structure, steering,
suspension, wheels, tires, and
exhaust system for damage and
check the fuel lines and cooling
system for any leakage.
The vehicle requires more frequent
service due to off-road use. Refer
to the Maintenance Schedule for
additional information.