transmission HUMMER H3 2009 Service Manual

Use the following procedure to tow
the vehicle:
1. Put the transmission in P (Park)
for an automatic transmission or
in 1 (First) for a manual
transmission.
2. Turn the engine off, but leave the
ignition in ACC/ACCESSORY.
3. Firmly set the parking brake.
4. Securely attach the vehicle being
towed to the tow vehicle.
{CAUTION
Shifting a full-time
four-wheel-drive vehicle’s
transfer case into N (Neutral)
can cause the vehicle to roll
even if the automatic transmission
is in P (Park) or the manual
transmission is in any gear. You
or others could be injured. Make
sure the parking brake is rmly
set before the transfer case is
shifted to N (Neutral).5. Shift the transfer case to
N (Neutral). SeeFull-Time
Four-Wheel Drive on page 2-24
for the proper procedure to
select the N (Neutral) position for
the vehicle.
6. Release the parking brake only
after the vehicle being towed is
rmly attached to the tow vehicle.
7. Make sure the ignition is in
ACC/ACCESSORY.
When towing the vehicle for
extended periods of time, start the
vehicle as often as possible to
prevent battery drain. This should
only be done when the tow
vehicle is parked.
After towing, see “Shifting Out of
NEUTRAL” underFull-Time
Four-Wheel Drive on page 2-24.
Dolly Towing
Notice:Dolly towing the vehicle
will damage drivetrain
components. Do not dolly tow the
vehicle.
The vehicle cannot be dolly towed.
If the vehicle must be towed
behind another vehicle, use the
dinghy towing procedure explained
previously.
Driving Your Vehicle 4-41

Do not tow a trailer at all during
the rst 500 miles (800 km) the
new vehicle is driven. The
engine, axle or other parts could
be damaged.
Then, during the rst 500 miles
(800 km) that a trailer is towed,
do not drive over 50 mph
(80 km/h) and do not make starts
at full throttle. This helps the
engine and other parts of
the vehicle wear in at the
heavier loads.
Vehicles with an automatic
transmissions can tow in
D (Drive). Shift the transmission
to a lower gear if the
transmission shifts too often
under heavy loads and/or hilly
conditions. For vehicles with
a manual transmission, it is better
not to use the highest gear.
This vehicle has a Hill Start
Assist feature, which may
be useful when the vehicle is
stopped on a grade. SeeBraking
on page 4-3for more information.
Three important considerations have
to do with weight:
The weight of the trailer
The weight of the trailer tongue
The weight on the vehicle’s tires
Weight of the Trailer
How heavy can a trailer safely be?
It depends on how the rig is
used. For example, speed, altitude,
road grades, outside temperature
and how much the vehicle is used to
pull a trailer are all important. It
can depend on any special
equipment on the vehicle, and the
amount of tongue weight the vehicle
can carry. See “Weight of the
Trailer Tongue” later in this section
for more information.
Driving Your Vehicle 4-43

Maximum trailer weight is calculated
assuming only the driver is in the
tow vehicle and it has all the
required trailering equipment. Theweight of additional optional
equipment, passengers and cargo in
the tow vehicle must be subtracted
from the maximum trailer weight.Use the following chart to determine
how much the vehicle can weigh,
based upon the vehicle model
and options.
Vehicle
Axle Ratio Maximum Trailer Weight *GCWR
H3 3.7L L5 Engine, Automatic
Transmission 4.56
4,500 lbs (2 041 kg) 9,500 lbs (4 309 kg)
3.7L L5 Engine, Manual
Transmission 4.56
3,000 lbs (1 361 kg) 8,000 lbs (3 629 kg)
5.3L V8 Engine, Automatic
Transmission 4.10
6,000 lbs (2 721 kg) 11,400 lbs (5 171 kg)
H3T 3.7L L5 Engine, Automatic
Transmission 4.56
4,400 lbs (1 996 kg) 9,500 lbs (4 309 kg)
3.7L L5 Engine, Manual
Transmission 4.56
2,900 lbs (1 315 kg) 8,000 lbs (3 629 kg)
5.3L V8 Engine, Automatic
Transmission 4.10
5,900 lbs (2 676 kg) 11,400 lbs (5 171 kg)
*The Gross Combination Weight Rating (GCWR) in the total allowable weight of the completely loaded vehicle and
trailer including any passengers, cargo, equipment and conversions. The GCWR for the vehicle should not be
exceeded.
Ask your dealer/retailer for our
trailering information or advice, or
write us at our Customer Assistance Offices. See
Customer Assistance
Offices on page 7-4 for more
information.
4-44 Driving Your Vehicle

Making Turns
Notice:Making very sharp turns
while trailering could cause
the trailer to come in contact with
the vehicle. The vehicle could
be damaged. Avoid making very
sharp turns while trailering.
When turning with a trailer, make
wider turns than normal. Do this
so the trailer won’t strike soft
shoulders, curbs, road signs, trees
or other objects. Avoid jerky or
sudden maneuvers. Signal well in
advance.
Turn Signals When Towing a
Trailer
The arrows on the instrument panel
ash whenever signaling a turn
or lane change. Properly hooked up,
the trailer lamps also ash, telling
other drivers the vehicle is turning,
changing lanes or stopping.When towing a trailer, the arrows
on the instrument panel ash
for turns even if the bulbs on the
trailer are burned out. For this
reason you may think other drivers
are seeing the signal when they
are not. It is important to check
occasionally to be sure the trailer
bulbs are still working.
Driving On Grades
Reduce speed and shift to a lower
gearbeforestarting down a long
or steep downgrade. If the
transmission is not shifted down, the
brakes might have to be used so
much that they would get hot and no
longer work well.
Vehicles with an automatic
transmission can tow in D (Drive).
Shift the transmission to a lower
gear if the transmission shifts
too often under heavy loads and/or
hilly conditions. For vehicles with
a manual transmission, it is
better not to use the highest gear.When towing at high altitude on
steep uphill grades, consider
the following: Engine coolant will
boil at a lower temperature than at
normal altitudes. If the engine is
turned off immediately after towing
at high altitude on steep uphill
grades, the vehicle may show signs
similar to engine overheating. To
avoid this, let the engine run
while parked, preferably on level
ground, with the automatic
transmission in P (Park) for a
few minutes before turning the
engine off. For vehicles with manual
transmissions, let the engine run
while parked, preferably on
level ground, with the transmission
out of gear and the parking
brake applied, for a few minutes
before turning the engine off. If the
overheat warning comes on,
seeEngine Overheating on
page 5-27.
Driving Your Vehicle 4-49

Parking on Hills
{CAUTION
Parking the vehicle on a hill with
the trailer attached can be
dangerous. If something goes
wrong, the rig could start to move.
People can be injured, and both
the vehicle and the trailer can be
damaged. When possible, always
park the rig on a at surface.
If parking the rig on a hill:
1. Press the brake pedal, but do
not shift into P (Park) yet for
vehicles with an automatic
transmission, or into gear for
vehicles with a manual
transmission. Turn the wheels
into the curb if facing downhill or
into traffic if facing uphill.2. Have someone place chocks
under the trailer wheels.
3. When the wheel chocks are in
place, release the brake pedal
until the chocks absorb the load.
4. Reapply the brake pedal.
Then apply the parking brake and
shift into P (Park) for vehicles
with an automatic transmission or
into gear for vehicles with a
manual transmission.
5. Release the brake pedal.
Leaving After Parking on
a Hill
The vehicle has a Hill Start Assist
feature, which may be useful
when stopped on a grade. See
Braking on page 4-3for more
information.
1. Apply and hold the brake pedal
while you:
start the engine,
shift into a gear, and
release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is
clear of the chocks.
4. Stop and have someone pick up
and store the chocks.
4-50 Driving Your Vehicle

Maintenance When Trailer
Towing
The vehicle needs service more
often when pulling a trailer. See this
manual’s Maintenance Schedule
or Index for more information.
Things that are especially important
in trailer operation are automatic
transmission uid, engine oil,
axle lubricant, belts, cooling system
and brake system. It is a good
idea to inspect these before and
during the trip.
Check periodically to see that all
hitch nuts and bolts are tight.
Trailer Wiring Harness
Light-Duty Trailer Wiring Package
If the vehicle does not have a
trailer towing package, the chassis
harness will contain the following
blunt cut circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn
Signal
White: Ground
Brown: Tail Lamps
To add a trailer towing wiring
package, have it installed by your
dealer/retailer or a qualied
service center. Also, seeAdd-On
Electrical Equipment on page 5-91
for more information.Heavy-Duty Trailer Wiring
Package
If the vehicle has a trailer towing
package, the rear bumper harness
will have a seven-pin universal
heavy-duty trailer connector
attached to a bracket on the hitch
platform.
Driving Your Vehicle 4-51

Service and
Appearance Care
Service
Service...............................5-3
Accessories and
Modications.....................5-3
California Proposition
65 Warning.......................5-4
California Perchlorate
Materials Requirements.....5-4
Doing Your Own
Service Work....................5-4
Adding Equipment to the
Outside of the Vehicle........5-5
Fuel
Fuel....................................5-5
Gasoline Octane.................5-5
Gasoline Specications.......5-5
California Fuel....................5-5
Additives.............................5-6
Fuels in Foreign
Countries..........................5-7
Filling the Tank...................5-7
Filling a Portable Fuel
Container..........................5-8
Checking Things Under
the Hood
Checking Things Under
the Hood..........................5-9
Hood Release.....................5-9
Engine Compartment
Overview.........................5-10
Engine Oil.........................5-13
Engine Oil Life System.....5-15
Engine Air Cleaner/Filter. . .5-17
Automatic Transmission
Fluid................................5-18
Manual Transmission
Fluid................................5-20
Hydraulic Clutch................5-21
Cooling System.................5-22
Engine Coolant.................5-23
Engine Overheating...........5-27
Engine Fan Noise.............5-28
Power Steering Fluid.........5-29
Windshield Washer Fluid. . .5-30
Brakes..............................5-30
Battery..............................5-33
Jump Starting...................5-34
Rear Axle
Rear Axle.........................5-38
Four-Wheel Drive
Four-Wheel Drive..............5-38
Front Axle
Front Axle.........................5-39
Headlamp Aiming
Headlamp Aiming..............5-39
Bulb Replacement
Bulb Replacement.............5-41
Halogen Bulbs..................5-41
Headlamps........................5-41
Taillamps, Turn Signal,
Stoplamps and Back-up
Lamps (H3)
.....................5-42
Taillamps, Turn Signal,
Stoplamps and Back-up
Lamps (H3T)
...................5-42
License Plate Lamp..........5-43
Replacement Bulbs...........5-43
Service and Appearance Care 5-1

A. Windshield Washer Fluid
Reservoir. See “Adding Washer
Fluid” underWindshield
Washer Fluid on page 5-30.
B. Engine Coolant Recovery Tank.
SeeEngine Coolant on
page 5-23.
C.Engine Air Cleaner/Filter on
page 5-17.
D. Power Steering Fluid Reservoir.
SeePower Steering Fluid on
page 5-29.
E. Automatic Transmission Fluid
Dipstick (If Equipped). See
“Checking the Fluid Level”
underAutomatic Transmission
Fluid on page 5-18.
F. Engine Oil Fill Cap. See “When
to Add Engine Oil” under
Engine Oil on page 5-13.G. Radiator Pressure Cap.
SeeCooling System on
page 5-22.
H. Remote Negative (−) Terminal
(GND). SeeJump Starting on
page 5-34.
I. Engine Oil Dipstick. See
“Checking Engine Oil” under
Engine Oil on page 5-13.
J. Positive (+) Battery Terminal.
SeeJump Starting on
page 5-34.
K. Brake Fluid Reservoir.
See “Brake Fluid” under
Brakes on page 5-30.
L.Engine Compartment Fuse Block
on page 5-92.
M.Battery on page 5-33.
N. Hydraulic Clutch Fluid Reservoir
(If Equipped). SeeHydraulic
Clutch on page 5-21.
Service and Appearance Care 5-11

A.Engine Air Cleaner/Filter on
page 5-17.
B. Air Filter Restriction Indicator
(If Equipped). SeeEngine Air
Cleaner/Filter on page 5-17.
C. Windshield Washer Fluid
Reservoir. See “Adding Washer
Fluid” underWindshield
Washer Fluid on page 5-30.
D. Engine Coolant Recovery Tank.
SeeEngine Coolant on
page 5-23.
E. Automatic Transmission
Fluid Dipstick (If Equipped).
See “Checking the Fluid Level”
underAutomatic Transmission
Fluid on page 5-18.
F. Engine Oil Dipstick. See
“Checking Engine Oil” under
Engine Oil on page 5-13.G. Engine Oil Fill Cap. See “When
to Add Engine Oil” underEngine
Oil on page 5-13.
H. Brake Fluid Reservoir.
See “Brake Fluid” underBrakes
on page 5-30.
I.Battery on page 5-33.
J. Power Steering Fluid Reservoir.
SeePower Steering Fluid on
page 5-29.
K.Engine Compartment Fuse Block
on page 5-92.
L. Radiator Pressure Cap.
SeeCooling System on
page 5-22.Engine Oil
Checking Engine Oil
It is a good idea to check the
engine oil every time you get fuel.
In order to get an accurate reading,
the oil must be warm and the
vehicle must be on level ground.
The engine oil dipstick handle
is a yellow loop. SeeEngine
Compartment Overview on
page 5-10for the location of the
engine oil dipstick.
1. Turn off the engine and give the
oil several minutes to drain back
into the oil pan. If you do not
do this, the oil dipstick might not
show the actual level.
2. Pull out the dipstick and clean it
with a paper towel or cloth,
then push it back in all the way.
Remove it again, keeping the
tip down, and check the level.
Service and Appearance Care 5-13

Automatic Transmission
Fluid
When to Check and Change
Automatic Transmission Fluid
A good time to check the automatic
transmission uid level is when
the engine oil is changed.
Change the uid and lter at the
intervals listed inAdditional
Required Services on page 6-6, and
be sure to use the transmission
uid listed inRecommended Fluids
and Lubricants on page 6-12.
How to Check Automatic
Transmission Fluid
Because this operation can be a
little difficult, you may choose
to have this done at the
dealer/retailer service department.
If adding it yourself, be sure to follow
all the instructions here, or there
could be a false reading on the
dipstick.Notice:Too much or too little
uid can damage your
transmission. Too much can
mean that some of the uid could
come out and fall on hot engine
parts or exhaust system parts,
starting a re. Too little uid
could cause the transmission to
overheat. Be sure to get an
accurate reading if you check
your transmission uid.
Wait at least 30 minutes before
checking the transmission uid level
if you have been driving:
When outside temperatures are
above 90°F (32°C).
At high speed for quite a while.
In heavy traffic — especially
in hot weather.
While pulling a trailer.
To get the right reading, the uid
should be at normal operating
temperature, which is 180°F to
200°F (82°C to 93°C).Get the vehicle warmed up by
driving about 15 miles (24 km) when
outside temperatures are above
50°F (10°C). If it is colder than
50°F (10°C), drive the vehicle
in 3 (Third) until the engine
temperature gage moves and then
remains steady for 10 minutes.
A cold uid check can be made after
the vehicle has been sitting for
eight hours or more with the engine
off, but this is used only as a
reference. Let the engine run at
idle for ve minutes if outside
temperatures are 50°F (10°C) or
more. If it is colder than 50°F (10°C),
the engine might have to idle
longer. Should the uid level
be low during this cold check,
check the uid hot before adding
uid. Checking the uid hot gives
a more accurate reading of the
uid level.
5-18 Service and Appearance Care