transmission GMC SIERRA 2010 Service Manual

.Sound the horn as you approach the top of the hill
to let opposing traffic know you are there.
.Use headlamps even during the day to make the
vehicle more visible to oncoming traffic.
{WARNING:
Driving to the top (crest) of a hill at full speed can
cause an accident. There could be a drop-off,
embankment, cliff, or even another vehicle. You
could be seriously injured or killed. As you near
the top of a hill, slow down and stay alert.
If the vehicle stalls, or is about to stall, and you cannot
make it up the hill:
.Push the brake pedal to stop the vehicle and
keep it from rolling backwards and apply the
parking brake.
.If the engine is still running, shift the transmission
to R (Reverse), release the parking brake, and
slowly back down the hill in R (Reverse).
.If the engine has stopped running, you need to
restart it. With the brake pedal pressed and the
parking brake still applied, shift the transmission to
P (Park) and restart the engine. Then, shift to
R (Reverse), release the parking brake, and slowly
back down the hill as straight as possible in
R (Reverse).
.While backing down the hill, put your left hand
on the steering wheel at the 12 o'clock position
so you can tell if the wheels are straight and can
maneuver as you back down. It is best to back
down the hill with the wheels straight rather than
in the left or right direction. Turning the wheel too
far to the left or right will increase the possibility
of a rollover.
Things not to do if the vehicle stalls, or is about to stall,
when going up a hill:
.Never attempt to prevent a stall by shifting into
N (Neutral) to rev-up the engine and regain forward
momentum. This will not work. The vehicle can roll
backward very quickly and could go out of control.
.Never try to turn around if about to stall when
going up a hill. If the hill is steep enough to stall
the vehicle, it is steep enough to cause it to roll
over. If you cannot make it up the hill, back straight
down the hill.
5-17

If, after stalling, you try to back down the hill and decide
you just cannot do it, set the parking brake, put your
transmission in P (Park), and turn off the engine. Leave
the vehicle and go get some help. Exit on the uphill side
and stay clear of the path the vehicle would take if it
rolled downhill. Do not shift the transfer case to Neutral
when you leave the vehicle. Leave it in some gear.
{WARNING:
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 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.
5-18

{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. Vehicles are much more likely to stall when going uphill,
but if it happens when going downhill:
1. Stop the vehicle by applying the regular 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.
5-19

Hill and Mountain Roads
Driving on steep hills or through mountains is different
than driving on flat or rolling terrain. Tips for driving in
these conditions include:
.Keep the vehicle serviced and in good shape.
.Check all fluid levels and brakes, tires, cooling
system, and transmission.
.Going down steep or long hills, shift to a
lower gear.
{WARNING:
If you do not shift down, the brakes could get so
hot that they would not work well. You would then
have poor braking or even none going down a hill.
You could crash. Shift down to let the engine
assist the brakes on a steep downhill slope.
{WARNING:
Coasting downhill in N (Neutral) or with the
ignition off is dangerous. The brakes will have to
do all the work of slowing down and they could
get so hot that they would not work well. You
would then have poor braking or even none going
down a hill. You could crash. Always have the
engine running and the vehicle in gear when
going downhill.
.Stay in your own lane. Do not swing wide or cut
across the center of the road. Drive at speeds that
let you stay in your own lane.
.Top of hills: Be alert—something could be in your
lane (stalled car, accident).
.Pay attention to special road signs (falling rocks
area, winding roads, long grades, passing or
no-passing zones) and take appropriate action.
See Off-Road Driving
on page 5‑11for information
about driving off-road.
5-25

If Your Vehicle is Stuck in Sand,
Mud, Ice, or Snow
Slowly and cautiously spin the wheels to free the
vehicle when stuck in sand, mud, ice, or snow. See
Rocking Your Vehicle to Get It Out on page 5‑28.
If the vehicle has a traction system, it can often help
to free a stuck vehicle. Refer to the vehicle's traction
system in the Index. If stuck too severely for the traction
system to free the vehicle, turn the traction system off
and use the rocking method.
{WARNING:
If the vehicle's tires spin at high speed, they can
explode, and you or others could be injured.
The vehicle can overheat, causing an engine
compartment fire or other damage. Spin the
wheels as little as possible and avoid going above
55 km/h (35 mph) as shown on the speedometer.
For information about using tire chains on the vehicle,
see Tire Chains on page 6‑89.
Rocking Your Vehicle to Get It Out
Turn the steering wheel left and right to clear the
area around the front wheels. For four-wheel-drive
vehicles, shift into Four‐Wheel High. For vehicles with
StabiliTrak
®, turn the traction control part of the system
off. Shift back and forth between R (Reverse) and a
forward gear, spinning the wheels as little as possible.
To prevent transmission wear, wait until the wheels stop
spinning before shifting gears. Release the accelerator
pedal while shifting, and press lightly on the accelerator
pedal when the transmission is in gear. Slowly spinning
the wheels in the forward and reverse directions causes
a rocking motion that could free the vehicle. If that does
not get the vehicle out after a few tries, it might need
to be towed out. Recovery hooks can be used, if the
vehicle has them. If the vehicle does need to be towed
out, see Towing Your Vehicle on page 5‑43.
5-28

Here are some important things to consider before
recreational vehicle towing:
.What is the towing capacity of the towing vehicle?
Be sure to read the tow vehicle manufacturer's
recommendations.
.What is the distance that will be travelled? Some
vehicles have restrictions on how far and how long
they can tow.
.Is the proper towing equipment going to be used?
See your dealer/retailer or trailering professional
for additional advice and equipment
recommendations.
.Is the vehicle ready to be towed? Just as preparing
the vehicle for a long trip, make sure the vehicle is
prepared to be towed. SeeBefore Leaving on a
Long Trip on page 5‑24.
Dinghy Towing
Two-Wheel-Drive Vehicles
Notice: If the vehicle is towed with all four wheels
on the ground, the drivetrain components could be
damaged. The repairs would not be covered by the
vehicle warranty. Do not tow the vehicle with all
four wheels on the ground.
Two-wheel-drive vehicles should not be towed
with all four wheels on the ground. Two-wheel-drive
transmissions have no provisions for internal lubrication
while being towed.
5-44

Four-Wheel-Drive Vehicles
Use the following procedure to dinghy tow a
four-wheel-drive vehicle:1. Position the vehicle being towed behind the tow vehicle and shift the transmission to P (Park).
2. Turn the engine off and firmly set the parking brake.
3. Securely attach the vehicle being towed to the tow vehicle.
{WARNING:
Shifting a four-wheel-drive vehicle's transfer case
into N (Neutral) can cause the vehicle to roll even
if the transmission is in P (Park). The driver or
others could be injured. Make sure the parking
brake is firmly set before the transfer case is
shifted to N (Neutral).
4. Shift the transfer case to N (Neutral). See “Shifting
into Neutral” underFour-Wheel Drive
on
page 3‑36for the proper procedure to select the
Neutral position for the vehicle.
5. Release the parking brake only after the vehicle being towed is firmly attached to the towing
vehicle.
6. Turn the ignition to LOCK/OFF and remove the key —the steering wheel will still turn.
After towing, see “Shifting Out of Neutral” under
Four-Wheel Drive
on page 3‑36for the proper
procedure to take the vehicle out of the Neutral position.
5-45

Dolly Towing
Front Towing
(Front Wheels Off the Ground)
Two-Wheel-Drive Vehicles
Notice:If a two-wheel-drive vehicle is towed with
the rear wheels on the ground, the transmission
could be damaged. The repairs would not be
covered by the vehicle warranty. Never tow the
vehicle with the rear wheels on the ground.
Two-wheel-drive vehicles should not be towed with the
rear wheels on the ground. Two-wheel-drive
transmissions have no provisions for internal lubrication
while being towed.
To dolly tow a two‐wheel‐drive vehicle, the vehicle must
be towed with the rear wheels on the dolly. See “Rear
Towing (Rear Wheels Off the Ground)” later in this
section for more information.
5-46

Four-Wheel-Drive Vehicles
Use the following procedure to dolly tow a
four-wheel-drive vehicle from the front:1. Attach the dolly to the tow vehicle following the dolly manufacturer's instructions.
2. Drive the front wheels onto the dolly.
3. Shift the transmission to P (Park).
4. Firmly set the parking brake.
{WARNING:
Shifting a four-wheel-drive vehicle's transfer case
into N (Neutral) can cause the vehicle to roll even
if the transmission is in P (Park). The driver or
others could be injured. Make sure the parking
brake is firmly set before the transfer case is
shifted to N (Neutral).
5. Use an adequate clamping device designed for towing to ensure that the front wheels are locked
into the straight position.
6. Secure the vehicle to the dolly following the manufacturer's instructions.
7. Shift the transfer case to N (Neutral). See “Shifting
into Neutral” underFour-Wheel Drive
on
page 3‑36for the proper procedure to select the
neutral position for the vehicle.
8. Release the parking brake only after the vehicle being towed is firmly attached to the towing
vehicle.
9. Turn the ignition to LOCK/OFF.
After towing, see “Shifting Out of Neutral” under
Four-Wheel Drive on page 3‑36.
5-47

Rear Towing
(Rear Wheels Off the Ground)Two‐Wheel‐Drive Vehicles
Use the following procedure to dolly tow a
two-wheel-drive vehicle from the rear:
1. Attach the dolly to the tow vehicle following the dolly manufacturer's instructions.
2. Drive the rear wheels onto the dolly.
3. Firmly set the parking brake. See Parking Brake
on page 3‑50.
4. Put the transmission in P (Park).
5. Secure the vehicle to the dolly following the manufacturer's instructions.
6. Use an adequate clamping device designed for towing to ensure that the front wheels are locked
into the straight position.
7. Turn the ignition to LOCK/OFF.
5-48