2004 CHEVROLET ASTRO CARGO VAN service

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. 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 ller 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 ller
plug hole.
When the differential is at operating temperature
(warm), add enough lubricant to raise the level to
the bottom of the ller 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 6-28.
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Tires
Your new vehicle comes with high-quality tires made by
a leading tire manufacturer. If you ever have questions
about your tire warranty and where to obtain service,
see your GM Warranty booklet for details. For additional
information refer to the tire manufacturer’s booklet
included with your vehicle’s Owner’s Manual.{CAUTION:
Poorly maintained and improperly used tires
are dangerous.
Overloading your tires can cause
overheating as a result of too much
friction. You could have an air-out and
a serious accident. SeeLoading Your
Vehicle on page 4-29.
Underinated tires pose the same danger
as overloaded tires. The resulting accident
could cause serious injury. Check all tires
frequently to maintain the recommended
pressure. Tire pressure should be checked
when your tires are cold.
Overinated tires are more likely to be
cut, punctured or broken by a sudden
impact — such as when you hit a pothole.
Keep tires at the recommended pressure.
Worn, old tires can cause accidents.
If your tread is badly worn, or if your tires
have been damaged, replace them.
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(A) Tire Size Code:The tire size code is a combination
of letters and numbers used to dene a particular
tire’s width, height, aspect ratio, construction type and
service description. See the “Tire Size Code” illustration
later in this section for more detail.
(B) Tire Performance Criteria Specication
(TPC Spec):Original equipment tires designed to
GM’s specic tire performance criteria have a
TPC specication code molded onto the sidewall.
GM’s TPC specications meet or exceed all federal
safety guidelines.
(C) Department of Transportation (DOT):The
Department of Transportation (DOT) code indicates that
the tire is in compliance with the U.S. Department of
Transportation Motor Vehicle Safety Standards.
(D) Tire Identication Number (TIN):The letters
and numbers following DOT code are the Tire
Identication Number (TIN). The TIN shows the
manufacturer and plant code, tire size, and date
the tire was manufactured. The TIN is molded onto
both sides of the tire, although only one side may
have the date of manufacture.(E) Tire Ply Material:The type of cord and number
of plies in the sidewall and under the tread.
(F) Uniform Tire Quality Grading (UTQG):Tire
manufacturers are required to grade tires based on
three performance factors: treadwear, traction and
temperature resistance. For more information, see
Uniform Tire Quality Grading on page 5-74.
(G) Maximum Cold Ination Load Limit:Maximum
load that can be carried and the maximum pressure
needed to support that load. For information on
recommended tire pressure seeInation - Tire Pressure
on page 5-70andLoading Your Vehicle on page 4-29.
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(A) Tire Size:The tire size code is a combination
of letters and numbers used to dene a particular
tire’s width, height, aspect ratio, construction type and
service description. See the “Tire Size” illustration
later in this section for more detail.
(B) Tire Performance Criteria Specication
(TPC Spec):Original equipment tires designed to
GM’s specic tire performance criteria have a
TPC specication code molded onto the sidewall.
GM’s TPC specications meet or exceed all federal
safety guidelines.
(C) Dual Tire Maximum Load:Maximum load that
can be carried and the maximum pressure needed to
support that load when used in a dual conguration.
For information on recommended tire pressure see
Ination - Tire Pressure on page 5-70andLoading
Your Vehicle on page 4-29.
(D) Department of Transportation (DOT):The
Department of Transportation (DOT) code indicates that
the tire is in compliance with the U.S. Department of
Transportation Motor Vehicle Safety Standards.
LT-Metric Tire
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(A) Temporary Use Only:The compact spare tire or
temporary use tire has a tread life of approximately
3,000 miles (5 000 km) and should not be driven
at speeds over 65 mph (105 km/h). The compact spare
tire is for emergency use when a regular road tire
has lost air and gone at. SeeCompact Spare Tire on
page 5-90andIf a Tire Goes Flat on page 5-77.
(B) Tire Ply Material:The type of cord and number
of plies in the sidewall and under the tread.
(C) Tire Identication Number (TIN):The Tire
Identication Number (TIN). The TIN shows the
manufacturer and plant code, tire size, and date the
tire was manufactured. The TIN is molded onto
both sides of the tire, although only one side may
have the date of manufacture.
(D) Maximum Cold Ination Load Limit:Maximum
load that can be carried and the maximum pressure
needed to support that load. SeeCompact Spare Tire
on page 5-90andLoading Your Vehicle on page 4-29.(E) Tire Ination:The temporary use tire or compact
spare tire should be inated to 60 psi (420 kPa).
For more information on tire pressure and ination see
Ination - Tire Pressure on page 5-70.
(F) Tire Size:A combination of letters and numbers
dene a tire’s width, height, aspect ratio, construction
type and service description. The letter “T” as the
rst character in the tire size means the tire is for
temporary use only.
(G) Tire Performance Criteria Specication
(TPC Spec):Original equipment tires designed to
GM’s specic tire performance criteria have a
TPC specication code molded onto the sidewall.
GM’s TPC specications meet or exceed all federal
safety guidelines.
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Tire Size
The following examples show the different parts of a
tire size.
(A) Passenger (P-Metric) Tire:The United States
version of a metric tire sizing system. The letter “P”
as the rst character in the tire size means a passenger
vehicle tire engineered to standards set by the U.S.
Tire and Rim Association.(B) Tire Width:The three-digit number indicates the
tire section width in millimeters from sidewall to sidewall.
(C) Aspect Ratio:A two-digit number that indicates
the tire height-to-width measurements. For example,
if the tire size aspect ratio is “75,” as shown in item “C”
of the illustration, it would mean that the tire’s sidewall
is 75% as high as it is wide.
(D) Construction Code:A letter code is used to
indicate the type of ply construction in the tire. The
letter “R” means radial ply construction; the letter “D”
means diagonal or bias ply construction; and the
letter “B” means belted-bias ply construction.
(E) Rim Diameter:Diameter of the wheel in inches.
(F) Service Description:The service description
indicates the load range and speed rating of a tire.
The load index can range from 1 to 279. Speed ratings
range from “A” to “Z”. The light truck tire size example
above shows dual or single tire congurations. Passenger (P-Metric) Tire
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(A) Light Truck (LT-Metric) Tire:The United States
version of a metric tire sizing system. The letter “LT”
as the rst two characters in the tire size means a light
truck tire engineered to standards set by the U. S.
Tire and Rim Association.
(B) Tire Width:The three-digit number indicates the
tire section width in millimeters from sidewall to sidewall.(C) Aspect Ratio:A two-digit number that indicates
the tire height-to-width measurements. For example,
if the tire size aspect ratio is “75,” as shown in item “C”
of the illustration, it would mean that the tire’s sidewall
is 75% as high as it is wide.
(D) Construction Code:A letter code is used to
indicate the type of ply construction in the tire. The letter
“R” means radial ply construction; the letter “D” means
diagonal or bias ply construction; and the letter “B”
means belted-bias ply construction.
(E) Rim Diameter:Diameter of the wheel in inches.
(F) Service Description:The service description
indicates the load range and speed rating of a tire.
The load index can range from 1 to 279. Speed ratings
range from “A” to “Z”. The light truck tire size example
above shows dual or single tire congurations. Light Truck (LT-Metric) Tire
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How to Check
Use a good quality pocket-type gage to check tire
pressure. You can’t tell if your tires are properly inated
simply by looking at them. Radial tires may look
properly inated even when they’re underinated.
Remove the valve cap from the tire valve stem. Press
the tire gage rmly onto the valve to get a pressure
measurement. If the cold tire ination pressure is low,
add air until you reach the recommended pressure
on the Certication/Tire label or the Tire and Loading
Information label.
If you overll 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 5-72andWheel Replacement
on page 5-75for 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 ratchet/wheel wrench to tighten the cable.
SeeChanging a Flat Tire on page 5-78.
The purpose of regular rotation is to achieve more
uniform wear for all tires on the vehicle. The rst rotation
is the most important. SeePart A: Scheduled
Maintenance Services on page 6-4.
When rotating your tires, always use the correct rotation
patterns shown here.
Don’t include the compact spare tire in your tire rotation.
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