Page 169 of 386

2-94 Air Pressure Gage (If Equipped)
If your vehicle has air
brakes, the air pressure gage
is located above the
switchbank in the center of
the instrument panel.
This gage shows the air pressure for both your front and
rear brake systems.
If the needle on the gage indicates that the air pressure is
below 60 to 75 psi (415 to 517 kPa), the low air warning
light will come on. An alarm will also sound if this
happens.
The yellow pointer shows the pressure available for the
front system, while the green pointer shows pressure for
the rear. There should be no more than 4 psi (28 kPa)
difference showing between the systems.
Don't drive until both pointers are showing at least
115 psi (793 kPa), so you'll have enough air if you
need to apply your brakes.
Air Filter Restriction Indicator (Option)
This optional gage is
located above the
switchbank in the center
of the instrument panel.
It monitors the engine
air filter.
As the filter gets dirty, the yellow indicator will begin to
rise. When it reaches 25 inches of vacuum on the scale,
the filter should be replaced.
After replacing the filter, reset the gage by pressing in
the yellow reset button at the bottom of the gage.
If you have a diesel engine, also see your Caterpillar
Operation & Maintenance Manual.
Page 293 of 386

6-39
Power Steering Fluid
See your Maintenance Schedule for when to check your
power steering fluid.
How To Check Power Steering Fluid
Check your power steering fluid only when the engine is
warm. If the engine isn't warm, you probably won't get
an accurate reading.
If the fluid level is
between the MIN and
MAX marks, you have
enough. If you need
fluid, add only enough
of the proper fluid to
bring it into view in
the sight glass.If your power steering fluid level is low, this can cause
the BRAKE or service brake soon warning lights to
come on. If either light remains on after you have added
power steering fluid to the proper level, then shut off the
engine for 10 seconds. This should reset the brake
warning lights. If one or both lights stay on though, see
ªHydraulic Brake Warning Lightsº in the Index.
What to Use
To determine what kind of fluid to use, see
ªRecommended Fluids and Lubricantsº in the Index.
NOTICE:
When adding power steering fluid or making a
complete fluid change, always use the proper
fluid. Failure to use the proper fluid can cause
leaks and damage hoses and seals.
Page 351 of 386

7-5
Scheduled Maintenance
The services shown in this schedule up to 100,000 miles
(166 000 km) should be repeated after 100,000 miles
(166 000 km) at the same intervals for the life of
this vehicle. The services shown after 100,000 miles
(166 000 km) should be repeated at the same miles (km)
after those intervals for the life of this vehicle.
Gasoline engine vehicles have a computer that lets you
know when to change your engine oil. This is not based
on mileage, but on engine revolutions and engine
operating temperature. When the computer has
calculated that the oil needs changing, the GM Oil Life
System will indicate that a change is necessary.
The ªFootnotesº at the end of this Maintenance
Schedule further explain maintenance services.
See ªScheduled Maintenance Supplementsº earlier in
this section.
100 Miles (160 km)
Wheel stud nut service. (46)
1,000 Miles (1 600 km)
Wheel stud nut service. (46)
Rear axle air shift motor service.(11)
L18/LB7 Engines Only: Clutch pedal free
travel service. (10)
7,500 Miles (12 000 km)
Gasoline Engine Only: Check Oil Life System.
If engine oil and filter are changed, reset system.
See ªEngine Oilº in the Index. (3)(9)
Check fluid levels (or every 3 months, whichever
occurs first). (1)(6)
Chassis lubrication service (or every 6 months,
whichever occurs first). (12)
Wheels and tires service. (15)
Parking brake service (or every 6 months, whichever
occurs first). (8)
L18/LB7 Engines Only: Clutch pedal free
travel service. (10)
10,000 Miles (16 000 km)
DURAMAX Diesel Only: Change engine oil
and filter (or every 12 months, whichever
occurs first). (2)(3)
Page 362 of 386

7-16
Footnotes
= The U.S. Environmental Protection Agency or the
California Air Resources Board has determined that the
failure to perform this maintenance item will not nullify
the emission warranty or limit recall liability prior to the
completion of the vehicle's useful life. We, however,
urge that all recommended maintenance services be
performed at the indicated intervals and the maintenance
be recorded.
(1) = If your vehicle has an Allison automatic
transmission, your GM owner's manual is supplemented
by an Allison Transmission Operator's Manual. Always
refer to these manuals for related maintenance services.
(2) = Refer to the Caterpillar Diesel Engine Operation
and Maintenance Manual for oil recommendations and
change intervals.
(3) = An Emission Control Service.
(4) = A Noise Emission Control Device.
(5) = Applies only to vehicles sold in the United States.(6) = Check fluid level in brake master cylinder, power
steering pump, axle, transmission and hydraulic spring
parking brake pump (if equipped). A low fluid level in
the brake master cylinder can indicate worn brake
linings and should be checked accordingly.
(7) = Inspect brake lines and hoses for proper hook
-up,
binding, leaks, cracks, chafing, etc. Inspect disc brake
pads for wear and rotors for surface condition. Inspect
caliper assemblies. Check brake pedal for excessive free
play or travel (or every 6 months, whichever occurs first)
and have serviced if needed. Check brakes more often if
driving habits and conditions result in frequent braking.
(8) = Inspect parking brake drum and linings for wear or
cracks and check linkage and adjustment.
(9) = This vehicle has the GM Oil Life System. This
system will show you when to change the engine oil and
filter
-- usually between 3,000 miles (5 000 km) and
7,500 miles (12 000 km) since your last oil change.
Under severe conditions, the indicator may come on
before 3,000 miles (5 000 km). Never drive your vehicle
more than 7,500 miles (12 000 km) or 12 months
without an oil and filter change.
Remember to reset the Oil Life System whenever the oil
is changed. For more information, see ªChange Oil
Lightº in the Index.