Page 346 of 411

Scheduled Maintenance
7-7
Long Trip/Highway Definition
Follow this scheduled maintenance only if none of
the conditions from the Short Trip/City Scheduled
Maintenance are true. Do not use this schedule if the
vehicle is used for trailer towing, driven in a dusty
area or used off paved roads. Use the Short Trip/City
schedule for these conditions.
Driving a vehicle with a fully warmed engine under
highway conditions will cause engine oil to break
down slower.
Long Trip/Highway Intervals
At 7,500 Miles (12 500 km): Drive Axle Service
(2500 and 3500 Series with locking differential only).
Every 7,500 Miles (12 500 km): Engine Oil and Filter
Change (or every 12 months, whichever occurs first).
Chassis Lubrication (or every 12 months, whichever
occurs first). Drive Axle Fluid Check. Tire Rotation.
Every 15,000 Miles (25 000 km): Gasoline Engine
Only: Noise Shields Inspection (GVWR above
10,000 lbs. only). Diesel Engine Only: Shields
and Underhood Insulation Inspection. Diesel Engine
Only: Thermostatically Controlled Engine Cooling
Fan Check (or every 12 months, whichever
occurs first). Diesel Engine Only: Air Intake
System Inspection.
Page 349 of 411
Short Trip/City Scheduled Maintenance
7-10
3,000 Miles (5 000 km)
Change engine oil and filter (or every 3 months, whichever occurs first).
An Emission Control Service.
Lubricate chassis components (or every 3 months, whichever occurs first).
(See footnote #.)
Check axle fluid level and add fluid as needed. 2500 and 3500 Series Only:
If your vehicle has a locking differential, drain fluid and refill at first engine
oil change.
6,000 Miles (10 000 km)
Change engine oil and filter (or every 3 months, whichever occurs first).
An Emission Control Service.
Lubricate chassis components (or every 3 months, whichever occurs first).
(See footnote #.)
Check axle fluid level and add fluid as needed.
Rotate tires. See ªTire Inspection and Rotationº in the Index for proper
rotation pattern and additional information. (See footnote +.)
ACTUAL
SERVICED BY:MILEAGE
DATE
ACTUAL
SERVICED BY:MILEAGE
DATE
Page 373 of 411

Long Trip/Highway Scheduled Maintenance
7-34
7,500 Miles (12 500 km)
Change engine oil and filter (or every 12 months, whichever occurs first).
An Emission Control Service.
Lubricate chassis components (or every 12 months, whichever occurs first).
(See footnote #.)
Check axle fluid level and add fluid as needed. 2500 and 3500 Series Only:
If your vehicle has a locking differential, drain fluid and refill at first engine
oil change.
Rotate tires. See ªTire Inspection and Rotationº in the Index for proper
rotation pattern and additional information. (See footnote +.)
15,000 Miles (25 000 km)
Change engine oil and filter (or every 12 months, whichever occurs first).
An Emission Control Service.
Lubricate chassis components (or every 12 months, whichever occurs first).
(See footnote #.)
Check axle fluid level and add fluid as needed.
Vehicles With GVWR Above 10,000 lbs. or Equipped with Diesel Engine
Only: Inspect shields for damage or looseness. Adjust or replace as required.
This is a Noise Emission Control Service. Applicable only to vehicles sold in
the United States.
ACTUAL
SERVICED BY:MILEAGE
DATE
ACTUAL
SERVICED BY:MILEAGE
DATE
Page 389 of 411
7-50
Weatherstrip Lubrication
Silicone grease on weatherstrips will make them last
longer, seal better, and not stick or squeak. Apply
silicone grease with a clean cloth. During very cold,
damp weather more frequent application may be
required. See ªRecommended Fluids and Lubricantsº
in the Index.
Automatic Transmission Check
Check the transmission fluid level; add if needed. See
ªAutomatic Transmission Fluidº in the Index. A fluid
loss may indicate a problem. Check the system and
repair if needed.At Least Once a Year
Key Lock Cylinders Service
Lubricate the key lock cylinders with the lubricant
specified in Part D.
Body Lubrication Service
Lubricate all hood hinges, hood prop rod pivot, fuel
filler door, rear compartment hinges, latches, locks,
hood latch assembly, secondary latch, pivots, spring
anchor, release pawl and any moving seat hardware.
Part D tells you what to use. More frequent
lubrication may be required when exposed to a
corrosive environment.
Page 390 of 411

7-51
Starter Switch Check
CAUTION:
When you are doing this check, the vehicle could
move suddenly. If it does, you or others could be
injured. Follow the steps below.
1. Before you start, be sure you have enough room
around the vehicle.
2. Firmly apply both the parking brake and the regular
brake. See ªParking Brakeº in the Index if necessary.
Do not use the accelerator pedal, and be ready to turn
off the engine immediately if it starts.
3. Try to start the engine in each gear. The starter
should work only in PARK (P) or NEUTRAL (N).
If the starter works in any other position, your
vehicle needs service.Automatic Transmission Shift Lock Control
System Check
CAUTION:
When you are doing this check, the vehicle could
move suddenly. If it does, you or others could be
injured. Follow the steps below.
1. Before you start, be sure you have enough
room around the vehicle. It should be parked on
a level surface.
2. Firmly apply the parking brake. See ªParking Brakeº
in the Index if necessary.
Be ready to apply the regular brake immediately if
the vehicle begins to move.
3. With the engine off, turn the key to the RUN
position, but don't start the engine. Without applying
the regular brake, try to move the shift lever out of
PARK (P) with normal effort. If the shift lever
moves out of PARK (P), your vehicle needs service.
Page 391 of 411

7-52
Ignition Transmission Lock Check
While parked, and with the parking brake set, try to turn
the ignition key to LOCK in each shift lever position.
The key should turn to LOCK only when the shift
lever is in PARK (P).
The key should come out only in LOCK.
Parking Brake and Automatic Transmission
PARK (P) Mechanism Check
CAUTION:
When you are doing this check, your vehicle
could begin to move. You or others could be
injured and property could be damaged. Make
sure there is room in front of your vehicle in case
it begins to roll. Be ready to apply the regular
brake at once should the vehicle begin to move.
Park on a fairly steep hill, with the vehicle facing
downhill. Keeping your foot on the regular brake,
set the parking brake.
To check the parking brake's holding ability: With
the engine running and transmission in
NEUTRAL (N), slowly remove foot pressure from
the regular brake pedal. Do this until the vehicle is
held by the parking brake only.
To check the PARK (P) mechanism's holding
ability: With the engine running, shift to PARK (P).
Then release the parking brake followed by the
regular brake.
Underbody Flushing Service
At least every spring, use plain water to flush any
corrosive materials from the underbody. Take care to
clean thoroughly any areas where mud and other debris
can collect.
Page 395 of 411

7-56
USAGEFLUID/LUBRICANT
Hydraulic
Brake SystemDelco Supreme 11 Brake Fluid
(GM Part No. 12377967 or
equivalent DOT
-3 brake fluid).
Windshield
Washer SolventGM Optikleen Washer
Solvent (GM Part No. 1051515)
or equivalent.
Parking Brake
Cable GuidesChassis Lubricant (GM Part
No. 12377985 or equivalent)
or lubricant meeting requirements
of NLGI # 2, Category LB
or GC
-LB.
Power
Steering SystemGM Power Steering Fluid
(GM Part No. 1052884
- 1 pint,
1050017
- 1 quart, or equivalent).
Automatic
TransmissionDEXRON-III Automatic
Transmission Fluid.
Key
Lock CylindersMulti-Purpose Lubricant,
Superlube (GM Part
No. 12346241 or equivalent).
USAGEFLUID/LUBRICANT
Chassis
LubricationChassis Lubricant (GM Part
No. 12377985 or equivalent)
or lubricant meeting requirements
of NLGI # 2, Category LB
or GC
-LB.
Front
Wheel BearingsWheel bearing lubricant meeting
requirements of NLGI # 2,
Category GC or GC
-LB (GM
Part No. 1051344 or equivalent).
Rear Axle
(1500 Series Only)SAE 75W-90 Synthetic
Axle Lubricant (GM Part
No. 12378261) or
equivalent meeting
GM Specification 9986115.
Rear Axle
(2500 and
3500 Series
with Standard
Differential Only)SAE 80W-90 Axle Lubricant
(GM Part No. 1052271
or equivalent).
Page 396 of 411
7-57
USAGEFLUID/LUBRICANT
Rear Axle
(2500 and
3500 Series
with Locking
Differential Only)Axle Lubricant; use only GM
Part No. 1052271. Do not add
friction modifier.
Propshaft
Splines and
Universal JointsChassis Lubricant (GM Part
No. 12377985 or equivalent)
or lubricant meeting requirements
of NLGI # 2, Category LB
or GC
-LB.
One-Piece
Propshaft SplineSpline Lubricant, Special
Lubricant (GM Part
No. 12345879) or lubricant
meeting requirements of
GM 9985830.
USAGEFLUID/LUBRICANT
Hood Latch
Assembly,
Secondary Latch,
Pivots, Spring
Anchor and
Release PawlLubriplate Lubricant Aerosol
(GM Part No. 12346293 or
equivalent) or lubricant meeting
requirements of NLGI # 2,
Category LB or GC
-LB.
Hood HingesMulti-Purpose Lubricant,
Superlube (GM Part
No. 12346241 or equivalent).
Weatherstrip
ConditioningDielectric Silicone Grease
(GM Part No. 12345579
or equivalent).
Weatherstrip
SqueaksSynthetic Grease with Teflon,
Superlube (GM Part
No. 12371287 or equivalent).