Page 414 of 552

MAINTENANCE PROCEDURES
The pages that follow contain therequiredmaintenance
services determined by the engineers who designed your
vehicle.
Besides the maintenance items for which there are fixed
maintenance intervals, there are other items that should
operate satisfactorily without periodic maintenance.
However, if a malfunction of these items does occur, it
could adversely affect the engine or vehicle performance.
These items should be inspected if a malfunction is
observed or suspected.
Engine Oil
Checking Oil Level
To assure proper lubrication of your vehicle’s engine, the
engine oil must be maintained at the correct level. Check
the oil level at regular intervals. The best time to check
the oil level is before starting the engine after it has been
parked overnight. When checking oil after operating the
engine, first ensure the engine is at full operating tem-
perature, then wait at least 30 minutes after engine
shutdown to check the oil.
Checking the vehicle while it’s on level ground will also
improve the accuracy of the oil level readings. Add oil
only when the level on the dipstick is below the “ADD”
mark. The total capacity from the low mark to the high
mark is 2 quarts (1.9 liters).
414 MAINTAINING YOUR VEHICLE
Page 445 of 552

accumulation of bugs, leaves, etc. If dirty, clean by gently
spraying water from a garden hose vertically down the
face of the condenser.
Check the coolant recovery bottle tubing for brittle rub-
ber, cracking, tears, cuts and tightness of the connection
at the bottle and radiator. Inspect the entire system for
leaks.
Extremely cold ambient temperature may require the
addition of a “winter front” for effective operation of the
cab heating/cooling system. Make certain that a percent-
age of the radiator is exposed for adequate air flow
through the charge air cooler and automatic transmission
oil cooler. The percentage of opening must be increased
with the increasing ambient air temperature and/or
engine load. If the cooling fan can be heard cycling
frequently, increase the size of the opening in the winter
front.Coolant bottle level check
The coolant reserve system provides a quick visual
method of determining that the coolant level is adequate.
With the engine idling, and warmed to the normal
operating temperature, the level of the coolant on the
coolant bottle should be between the fluid level marks.
Check the coolant level whenever the hood is raised.
The radiator normally remains completely full, so there is
no longer a need to remove the coolant pressure cap
except for checking coolant freeze point or replacement
with new antifreeze coolant.
WARNING!
Never add coolant to the radiator when the engine is
overheated. Do not loosen or remove pressure cap to
cool overheated engine! The coolant is under pres-
sure and severe scalding could result.
MAINTAINING YOUR VEHICLE 445
7
Page 454 of 552

Rear Axle And 4x4 Front Driving Axle Fluid Level
For Model 9.25 Front Axles and 10.5”/11.5” Rear Axles
refer to Fluids, Lubricants and Genuine Parts for the
correct lubricant type. For normal service, periodic fluid
level checks are not required. When the vehicle is ser-
viced for other reasons, the exterior surfaces of the axle
assembly should be inspected.
When checking the fluid level, the vehicle should be in a
level position. The fluid level should be 1/4” ± 1/4” (6.4
mm ± 6.4 mm) below the fill hole on the 9.25” Front Axle.
The fluid level should be 3/4” ± 1/4” (19 mm ± 6.4 mm)
below the fill hole on all 10.5” and 1/4” ± 1/4” (6.4 mm
± 6.4 mm) on 11.5” Rear Axles.
Drain And Refill
Vehicles operated in normal service do not have regularly
scheduled oil changes. If fluid has become contaminatedwith water or subjected to severe service, follow the
recommended change intervals in Maintenance Schedule
“B” in Section 8 of this manual.
Lubricant Selection
Refer to Fluids, Lubricants and Genuine Parts for the
correct lubricant type.
NOTE:The presence of water in the gear lubricant will
result in corrosion and possible failure of differential
components. Operation of the vehicle in water, as may be
encountered in some off-highway types of service, will
require draining and refilling the axle to avoid damage.
Limited-Slip Differentialsin vehicles equipped with
10.5”/11.5” AxlesDO NOT REQUIREany limited slip
oil additive (friction modifiers).
454 MAINTAINING YOUR VEHICLE
Page 495 of 552

•Off-road or desert operation.
•Extensive operation at high engine speeds (greater
than 2900 rpm) and loads (greater than 70% throttle).
NOTE:Most vehicles are operated under the conditions
listed for ScheduleB.
NOTE:IfANYof these apply to you then change your
coolant every 100,000 miles (160 000 km) or 60 months,
whichever comes first and follow schedule “B” of the
Maintenance Schedulessection of this manual.
Second is Schedule“A”. It is for vehicles that are not
operated under any of the conditions listed under Sched-
uleB.
Use the schedule that best describes your driving condi-
tions. Where time and mileage are listed, follow the
interval that occurs first.
CAUTION!
Failure to perform the required maintenance items
may result in damage to the vehicle.
At Each Stop for Fuel
•Check the engine oil level about 15 minutes after a
fully warmed engine is shut off. Checking the oil level
while the vehicle is on level ground will improve the
accuracy of the oil level reading. Add oil only when
the level is at or below the ADD or MIN mark.
•Check the windshield washer solvent and add if
required. When refilling the washer fluid reservoir,
take some washer fluid and apply it to a cloth or towel
and wipe clean the wiper blades, this will help blade
performance.
MAINTENANCE SCHEDULES 495
8
M
A
I
N
T
E
N
A
N
C
E
S
C
H
E
D
U
L
E
S
Page 511 of 552

MAINTENANCE SCHEDULES — 6.7L TURBO
DIESEL
CAUTION!
Failure to perform the required maintenance items
may result in damage to the vehicle.
At Each Stop for Fuel
•Check the engine oil level about 30 minutes after a
fully warmed engine is shut off. Checking the oil level
while the vehicle is on level ground will improve the
accuracy of the oil level reading. Add oil only when
the level is at or below the ADD or MIN mark.
•Check the windshield washer solvent and add if
required. When refilling the washer fluid reservoir,
take some washer fluid and apply it to a cloth or towel
and wipe clean the wiper blades, this will help blade
performance.Once a Month
•Check tire pressure and look for unusual wear or
damage.
•Inspect the batteries and clean and tighten the termi-
nals as required.
•Check the fluid levels of coolant reservoir, brake
master cylinder, and transmission and transfer case (if
equipped), add as needed.
•Check Filter Minder™. Replace air cleaner filter
element if necessary.
•Check all lights and all other electrical items for correct
operation.
•Drain water from the fuel filter.
SCHEDULE “A” 511
8
M
A
I
N
T
E
N
A
N
C
E
S
C
H
E
D
U
L
E
S