tow HUMMER H2 2008 Workshop Manual

Automatic Transmission Fluid
When to Check and Change Automatic
Transmission Fluid
It is usually not necessary to check the transmission
uid level. The only reason for uid loss is a
transmission leak or overheating the transmission. If you
suspect a small leak, then use the following checking
procedures to check the uid level. However, if there is
a large leak, then it may be necessary to have the
vehicle towed to a dealer/retailer service department and
have it repaired before driving the vehicle further.
Notice:Use of the incorrect automatic transmission
uid may damage your vehicle, and the damages
may not be covered by your warranty. Always
use the automatic transmission uid listed in
Recommended Fluids and Lubricants on page 6-12.
Change the uid and lter at the intervals listed in the
Maintenance Schedule. SeeScheduled Maintenance on
page 6-4. Be sure to use the transmission uid listed in
Recommended Fluids and Lubricants on page 6-12.
How to Check Automatic
Transmission Fluid
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.
Before checking the uid level, prepare your vehicle
as follows:
1. Start the engine and park your vehicle on a level
surface. Keep the engine running.
2. Apply the parking brake and place the shift lever
in PARK (P).
3. With your foot on the brake pedal, move the shift
lever through each gear range, pausing for about
three seconds in each range. Then, move the
shift lever back to PARK (P).
4. Allow the engine to idle (500 – 800 rpm) for at least
one minute. Slowly release the brake pedal.
5. Keep the engine running and press the Trip/Fuel
button or trip odometer reset stem until TRANS
TEMP (Transmission Temperature) displays on the
Driver Information Center (DIC).
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6. Using the TRANS TEMP reading, determine and
perform the appropriate check procedure. If the
TRANS TEMP reading is not within the required
temperature ranges, allow the vehicle to cool,
or operate the vehicle until the appropriate
transmission uid temperature is reached.
Cold Check Procedure
Use this procedure only as a reference to determine
if the transmission has enough uid to be operated
safely until a hot check procedure can be made.
The hot check procedure is the most accurate method
to check the uid level. Perform the hot check procedure
at the rst opportunity. Use this cold check procedure
to check uid level when the transmission temperature
is between 80°F and 90°F (27°C and 32°C).
1. Locate the transmission dipstick at the rear of the
engine compartment, on the passenger side of the
vehicle.
The dipstick handle has
this graphic. SeeEngine
Compartment Overview
on page 5-12for more
information.
2. Flip the handle up, and then pull out the dipstick
and wipe it with a clean rag or paper towel.3. Install the dipstick by pushing it back in all the way,
wait three seconds, and then pull it back out again.
4. Check both sides of the dipstick, and read the lower
level. Repeat the check procedure to verify the
reading.
5. If the uid level is below the COLD check band,
add only enough uid as necessary to bring the
level into the COLD band. It does not take
much uid, generally less than one pint (0.5L).
Do not overll.
6. Perform a hot check at the rst opportunity after
the transmission reaches a normal operating
temperature between 160°F to 200°F (71°C to 93°C).
7. If the uid level is in the acceptable range, push the
dipstick back in all the way, then ip the handle
down to lock the dipstick in place.
5-22

Hot Check Procedure
Use this procedure to check the transmission uid level
when the transmission uid temperature is between
160°F and 200°F (71°C and 93°C).
The hot check is the most accurate method to check the
uid level. The hot check should be performed at the
rst opportunity in order to verify the cold check.
The uid level rises as uid temperature increases, so it
is important to ensure the transmission temperature
is within range.
1. Locate the transmission dipstick at the rear of the
engine compartment, on the passenger side of
the vehicle.
The dipstick handle has
this graphic. SeeEngine
Compartment Overview
on page 5-12for more
information.
2. Flip the handle up, and then pull out the dipstick
and wipe it with a clean rag or paper towel.
3. Install the dipstick by pushing it back in all the way,
wait three seconds, and then pull it back out again.4. Check both sides of the dipstick, and read the lower
level. Repeat the check procedure to verify the
reading.
5. Safe operating level is within the HOT cross hatch
band on the dipstick. If the uid level is not within
the HOT band, and the transmission temperature is
between 160°F and 200°F (71°C and 93°C), add
or drain uid as necessary to bring the level into
the HOT band. If the uid level is low, add only
enough uid to bring the level into the HOT band.
It does not take much uid, generally less than
one pint (0.5L). Do not overll.
6. If the uid level is in the acceptable range, push the
dipstick back in all the way, then ip the handle
down to lock the dipstick in place.
5-23

If No Steam Is Coming From
Your Engine
The ENGINE OVERHEATED IDLE ENGINE message,
along with a low coolant condition, can indicate a
serious problem.
If you get an engine overheat warning, but see or hear
no steam, the problem may not be too serious.
Sometimes the engine can get a little too hot when you:
Climb a long hill on a hot day.
Stop after high-speed driving.
Idle for long periods in traffic.
Tow a trailer. SeeTowing a Trailer on page 4-55.
If you get the ENGINE COOLANT HOT message with
no sign of steam, try this for a minute or so:
1. Turn on your heater to full hot at the highest fan
speed and open the windows as necessary.
2. If you are in a traffic jam, shift to NEUTRAL (N);
otherwise, shift to the highest gear while
driving — DRIVE (D).
If you no longer have the overheat warning, you can
drive. Just to be safe, drive slower for about 10 minutes.
If the warning does not come back on, you can drive
normally.
If the warning continues and you have not stopped, pull
over, stop, and park your vehicle right away.If there is still no sign of steam, push down the
accelerator until the engine speed is about twice as fast
as normal idle speed for at least three minutes while
you are parked. If you still have the warning, turn off the
engine and get everyone out of the vehicle until it
cools down. Also, see “Overheated Engine Protection
Operating Mode” later in this section.
You may decide not to lift the hood but to get service
help right away.
Overheated Engine Protection
Operating Mode
If an overheated engine condition exists and the
ENGINE POWER IS REDUCED message is displayed,
an overheat protection mode which alternates ring
groups of cylinders helps prevent engine damage. In this
mode, you will notice a loss in power and engine
performance. This operating mode allows your vehicle
to be driven to a safe place in an emergency. Driving
extended miles (km) and/or towing a trailer in the
overheat protection mode should be avoided.
Notice:After driving in the overheated engine
protection operating mode, to avoid engine damage,
allow the engine to cool before attempting any repair.
The engine oil will be severely degraded. Repair the
cause of coolant loss, change the oil and reset the oil
life system. SeeEngine Oil on page 5-13.
5-28

5. With the coolant surge tank pressure cap off, start
the engine and let it run until you can feel the upper
radiator hose getting hot. Watch out for the engine
cooling fan.
By this time, the coolant level inside the coolant
surge tank may be lower. If the level is lower, add
more of the proper mixture to the coolant surge tank
until the level reaches the FULL COLD mark.
6. Then replace the pressure cap. Be sure the
pressure cap is hand-tight and fully seated.
7. Verify coolant level after engine is shut off and the
coolant is cold. If necessary, repeat coolant ll
procedure steps 1 through 7.
Engine Fan Noise
If your vehicle has a clutched engine cooling fan, when
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions, the fan is spinning slower and the clutch is
not fully engaged. This improves fuel economy and
reduces fan noise. Under heavy vehicle loading, trailer
towing, and/or high outside temperatures, the fan
speed increases as the clutch more fully engages, so
you may hear an increase in fan noise. This is normal
and should not be mistaken as the transmission slipping
or making extra shifts. It is merely the cooling system
functioning properly. The fan will slow down when
additional cooling is not required and the clutch
disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch partially
disengages.
If your vehicle has electric cooling fans, you may hear
the fans spinning at low speed during most everyday
driving. The fans may turn off if no cooling is required.
Under heavy vehicle loading, trailer towing, and/or
high outside temperatures, or if you are operating your
air conditioning system, the fans may change to
high speed and you may hear an increase in fan noise.
This is normal and indicates that the cooling system
is functioning properly. The fans will change to low
speed when additional cooling is no longer required.
5-33

{CAUTION:
Rust or dirt on a wheel, or on the parts to
which it is fastened, can make wheel nuts
become loose after time. The wheel could
come off and cause an accident. When
you change a wheel, remove any rust or
dirt from places where the wheel attaches
to the vehicle. In an emergency, you can
use a cloth or a paper towel to do this;
but be sure to use a scraper or wire brush
later, if needed, to get all the rust or dirt
off. SeeChanging a Flat Tire on page 5-78.
Make sure the spare tire is stored securely. Push,
pull, and then try to rotate or turn the tire. If it
moves, tighten the cable. SeeStoring a Flat or
Spare Tire and Tools (SUT) on page 5-94or
Storing a Flat or Spare Tire and Tools (SUV) on
page 5-96.
When It Is Time for New Tires
Various factors, such as maintenance, temperatures,
driving speeds, vehicle loading, and road conditions,
inuence when you need new tires.
One way to tell when it is
time for new tires is to
check the treadwear
indicators, which appear
when your tires have
only 1/16 inch (1.6 mm) or
less of tread remaining.
Some commercial
truck tires may not have
treadwear indicators.
5-69

If a Tire Goes Flat
It is unusual for a tire to blowout while you are driving,
especially if you maintain your vehicle’s tires properly.
If air goes out of a tire, it is much more likely to leak out
slowly. But if you should ever have a blowout, here
are a few tips about what to expect and what to do:
If a front tire fails, the at tire creates a drag that pulls
the vehicle toward that side. Take your foot off the
accelerator pedal and grip the steering wheel rmly.
Steer to maintain lane position, and then gently brake to
a stop well out of the traffic lane.
A rear blowout, particularly on a curve, acts much like a
skid and may require the same correction you would
use in a skid. In any rear blowout remove your foot from
the accelerator pedal. Get the vehicle under control
by steering the way you want the vehicle to go. It may
be very bumpy and noisy, but you can still steer.
Gently brake to a stop, well off the road if possible.{CAUTION:
Lifting a vehicle and getting under it to do
maintenance or repairs is dangerous without
the appropriate safety equipment and training.
The jack provided with your vehicle is
designed only for changing a at tire. If it is
used for anything else, you or others could be
badly injured or killed if the vehicle slips off
the jack. Use the jack provided with your
vehicle only for changing a at tire.
If a tire goes at, the next part shows how to use the
jacking equipment to change a at tire safely.
Changing a Flat Tire
If a tire goes at, avoid further tire and wheel damage
by driving slowly to a level place. Turn on your
hazard warning ashers.
5-78

{CAUTION:
Raising your vehicle with the jack improperly
positioned can damage the vehicle and even
make the vehicle fall. To help avoid personal
injury and vehicle damage, be sure to t the
jack lift head into the proper location before
raising the vehicle.
8. Turn the wheel wrench clockwise to raise the
vehicle. Raise the vehicle far enough off the ground
so there is enough room for the spare tire to
clear the ground.
9. Remove all the wheel
nuts and take off the
at tire.
{CAUTION:
Rust or dirt on a wheel, or on the parts to which
it is fastened, can make wheel nuts become
loose after time. The wheel could come off and
cause an accident. When you change a wheel,
remove any rust or dirt from places where the
wheel attaches to the vehicle. In an emergency,
you can use a cloth or a paper towel to do this;
but be sure to use a scraper or wire brush
later, if needed, to get all the rust or dirt off.
SeeChanging a Flat Tire on page 5-78.
10. Remove any rust or dirt
from the wheel bolts,
mounting surfaces
and spare wheel.
5-91

{CAUTION:
Never use oil or grease on studs or nuts.
Because the nuts might come loose.
The vehicle’s wheel could fall off, causing
a crash.
11. Install the spare tire.
12. Put the wheel nuts back on with the rounded end
of the nuts toward the wheel.
13. Tighten each wheel nut by hand. Then use the
wheel wrench to tighten the nuts by turning it
clockwise until the wheel is held against the hub.
You will not be tightening the nuts fully yet.
14. Lower the vehicle by turning the wheel wrench
counterclockwise. Then lower the jack completely.
5-92

Do not clean your vehicle using the following cleaners
or techniques:
Never use a knife or any other sharp object to
remove a soil from any interior surface.
Never use a stiff brush. It can cause damage to
your vehicle’s interior surfaces.
Never apply heavy pressure or rub aggressively
with a cleaning cloth. Use of heavy pressure
can damage your interior and does not improve the
effectiveness of soil removal.
Use only mild, neutral-pH soaps. Avoid laundry
detergents or dishwashing soaps with degreasers.
Using too much soap will leave a residue that
leaves streaks and attracts dirt. For liquid cleaners,
about 20 drops per gallon (3.78 L) of water is a
good guide.
Do not heavily saturate your upholstery while
cleaning.
Damage to your vehicle’s interior may result from
the use of many organic solvents such as naptha,
alcohol, etc.
Fabric/Carpet
Use a vacuum cleaner with a soft brush attachment
frequently to remove dust and loose dirt. A canister
vacuum with a beater bar in the nozzle may only be used
on oor carpet and carpeted oor mats. For soils, always
try to remove them rst with plain water or club soda.
Before cleaning, gently remove as much of the soil as
possible using one of the following techniques:
For liquids: gently blot the remaining soil with a paper
towel. Allow the soil to absorb into the paper towel
until no more can be removed.
For solid dry soils: remove as much as possible and
then vacuum.
To clean, use the following instructions:
1. Saturate a lint-free, clean white cloth with water or
club soda.
2. Wring the cloth to remove excess moisture.
3. Start on the outside edge of the soil and gently rub
toward the center. Continue cleaning, using a clean
area of the cloth each time it becomes soiled.
4. Continue to gently rub the soiled area until the
cleaning cloth remains clean.
5. If the soil is not completely removed, use a mild
soap solution and repeat the cleaning process
that was used with plain water.
5-101