2004 GMC SONOMA maintenance

Brake Adjustment
Every time you make a brake stop, your disc brakes
adjust for wear.
If you do not have four-wheel drive and your brake
pedal goes down farther than normal, your rear drum
brakes may need adjustment. Adjust them by backing up
and firmly applying the brakes a few times.
Replacing Brake System Parts
The braking system on a vehicle is complex. Its many
parts have to be of top quality and work well together if
the vehicle is to have really good braking. Your
vehicle was designed and tested with top-quality GM
brake parts. When you replace parts of your braking
system — for example, when your brake linings
wear down and you need new ones put in — be sure
you get new approved GM replacement parts. If you do
not, your brakes may no longer work properly. For
example, if someone puts in brake linings that are wrong
for your vehicle, the balance between your front and
rear brakes can change — for the worse. The braking
performance you have come to expect can change
in many other ways if someone puts in the wrong
replacement brake parts.
Battery
Your new vehicle comes with a maintenance free
ACDelco®battery. When it is time for a new battery, get
one that has the replacement number shown on the
original battery’s label. We recommend an ACDelco
®
battery. SeeEngine Compartment Overview on
page 5-12for battery location.
Warning:Battery posts, terminals and related
accessories contain lead and lead compounds,
chemicals known to the State of California to cause
cancer and reproductive harm. Wash hands after
handling.
5-40

Rear Axle
When to Check and Change Lubricant
It is not necessary to regularly check rear axle fluid
unless you suspect there is a leak or you hear an
unusual noise. A fluid loss could indicate a problem.
Have it inspected and repaired.
Refer to the Maintenance Schedule to determine how
often to check the lubricant and when to change it. See
Part A: Scheduled Maintenance Services on page 6-4.
How to Check Lubricant
To get an accurate reading, the vehicle should be on a
level surface.
If the level is below the bottom of the filler plug hole,
you’ll need to add some lubricant. Add enough lubricant
to raise the level to the bottom of the filler plug hole.
What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. SeePart D: Recommended
Fluids and Lubricants on page 6-32.
Four-Wheel Drive
Lubricant checks in this section also apply to these
vehicles. However, there are two additonal systems that
need lubrication.
Transfer Case
When to Check Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant. SeePart C: Periodic
Maintenance Inspections on page 6-30.
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How to Check Lubricant
To get and accurate reading, the vehicle should be on a
level service.
If the level is below the bottom of the filler plug hole,
you’ll need to add some lubricant. Remove the plug and
add enough lubricant to raise the level to the bottom
of the filler plug hole. Use care not to overtighten
the plug.
What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. SeePart D: Recommended
Fluids and Lubricants on page 6-32.
Front Axle
When to Check and Change Lubricant
Refer to the Maintenance Schedule to determine
how often to check the lubricant and when to change it.
SeePart A: Scheduled Maintenance Services on
page 6-4.
How to Check Lubricant
To get an accurate reading, the vehicle should be on a
level surface.
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If the level is below the bottom of the filler plug hole,
you may need to add some lubricant.
When the differential is cold, add enough lubricant to
raise the level to 1/2 inch (12 mm) below the filler
plug hole.
When the differential is at operating temperature
(warm), add enough lubricant to raise the level to the
bottom of the filler plug hole.
What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. SeePart D: Recommended
Fluids and Lubricants on page 6-32.
Bulb Replacement
SeeReplacement Bulbs on page 5-54for the proper
types of bulbs to use. For any bulb changing procedure
not listed in this section, contact your GM dealer’s
service department.
Halogen Bulbs
{CAUTION:
Halogen bulbs have pressurized gas inside
and can burst if you drop or scratch the bulb.
You or others could be injured. Be sure to read
and follow the instructions on the bulb
package.
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Replacement Bulbs
Exterior Lamp Bulb Number
Halogen Headlamps
Composite Low-Beam
Composite High-Beam9006 HB4 or
9006 LL
9005 HB3
Tail and Stoplamps 3057
Rear Sidemarker Lamps 194
Front Sidemarker Lamps 194NA
Front Turn Signal Lamps 3457A
Center High–Mounted Stoplamp 211–2
*For replacement bulbs not listed here, please
consult your dealer.
Windshield Wiper Blade
Replacement
Windshield wiper blades should be inspected at least
twice a year for wear and cracking. See “Wiper
Blade Check” underAt Least Twice a Year on
page 6-26.
Replacement blades come in different types and are
removed in different ways. For proper type and length,
seeNormal Maintenance Replacement Parts on
page 6-34.
Notice:Allowing the wiper blade arm to touch the
windshield when no wiper blade is installed
could damage the windshield. Any damage that
occurs would not be covered by your warranty. Do
not allow the wiper blade arm to touch the
windshield.
1. To remove the old wiper blades, lift the wiper arm
until it locks into a vertical position.
5-54

remove the valve cap from the tire valve stem. Press
the tire gage firmly onto the valve to get a pressure
measurement. If the cold tire inflation pressure matches
the recommended pressure on the tire and loading
information label, no further adjustment is necessary. If
the pressure is low, add air until you reach the
recommended amount.
If you overfill the tire, release air by pushing on the
metal stem in the center of the tire valve. Recheck the
tire pressure with the tire gage.
Be sure to put the valve caps back on the valve stems.
They help prevent leaks by keeping out dirt and
moisture.
Tire Inspection and Rotation
Tires should be rotated every 5,000 to 8,000 miles
(8 000 to 13 000 km).
Any time you notice unusual wear, rotate your tires as
soon as possible and check wheel alignment. Also
check for damaged tires or wheels. SeeWhen It Is Time
for New Tires on page 5-69andWheel Replacement
on page 5-72for more information.Make sure the spare tire is stored securely. Push, pull,
and then try to rotate or turn the tire. If it moves,
use the wheel wrench to tighten the cable. See
Changing a Flat Tire on page 5-75.
The purpose of regular rotation is to achieve more
uniform wear for all tires on the vehicle. The first rotation
is the most important. SeePart A: Scheduled
Maintenance Services on page 6-4, for scheduled
rotation intervals.
When rotating your tires, always use the correct rotation
pattern shown here.
If your vehicle has a compact spare tire or a spare tire
that does not match your vehicle’s road tires and
wheels, in size and type, do not include the spare in the
tire rotation.
5-68

{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 flat, the next part shows how to use your
jacking equipment to change a flat tire safely.
Changing a Flat Tire
If a tire goes flat, avoid further tire and wheel damage
by driving slowly to a level place. Turn on your
hazard warning flashers.
{CAUTION:
Changing a tire can cause an injury. The
vehicle can slip off the jack and roll over you
or other people. You and they could be badly
injured. Find a level place to change your tire.
To help prevent the vehicle from moving:
1. Set the parking brake rmly.
2. Put the shift lever in PARK (P).
3. Turn off the engine.
To be even more certain the vehicle won’t
move, you can put blocks at the front and rear
of the tire farthest away from the one being
changed. That would be the tire on the other
side of the vehicle, at the opposite end.
5-75

Finish Damage
Any stone chips, fractures or deep scratches in the
finish should be repaired right away. Bare metal
will corrode quickly and may develop into major repair
expense.
Minor chips and scratches can be repaired with touch-up
materials avaliable from your dealer. Larger areas of
finish damage can be corrected in your dealer’s
body and paint shop.
Underbody Maintenance
Chemicals used for ice and snow removal and dust
control can collect on the underbody. If these are not
removed, corrosion and rust can develop on the
underbody parts such as fuel lines, frame, floor pan and
exhaust system even though they have corrosion
protection.
At least every spring, flush these materials from the
underbody with plain water. Clean any areas where mud
and debris can collect. Dirt packed in close areas of
the frame should be loosened before being flushed.
Your dealer or an underbody car washing system can
do this for you.
Chemical Paint Spotting
Some weather and atmospheric conditions can create a
chemical fallout. Airborne pollutants can fall upon and
attack painted surfaces on your vehicle. This damage
can take two forms: blotchy, ring-shaped discolorations,
and small, irregular dark spots etched into the paint
surface.
Although no defect in the paint job causes this, GM will
repair, at no charge to the owner, the surfaces of
new vehicles damaged by this fallout condition within
12 months or 12,000 miles (20 000 km) of purchase,
whichever occurs first.
5-92