CAUTION!
•The catalytic converter requires the use of unleaded
fuel only. Leaded gasoline will destroy the effective-
ness of the catalyst as an emissions control device
and may seriously reduce engine performance and
cause serious damage to the engine.
• Damage to the catalytic converter can result if your
vehicle is not kept in proper operating condition. In
the event of engine malfunction, particularly involv-
ing engine misfire or other apparent loss of perfor-
mance, have your vehicle serviced promptly. Contin-
ued operation of your vehicle with a severe
malfunction could cause the converter to overheat,
resulting in possible damage to the converter and
vehicle.
Under normal operating conditions, the catalytic converter
will not require maintenance. However, it is important to
keep the engine properly tuned to assure proper catalyst
operation and prevent possible catalyst damage.
NOTE: Intentional tampering with emissions control sys-
tems can result in civil penalties being assessed against
you. In unusual situations involving grossly malfunctioning
engine operation, a scorching odor may suggest severe and
abnormal catalyst overheating. If this occurs, stop the
vehicle, turn off the engine and allow it to cool. Service,
including a tune-up to manufacturer’s specifications,
should be obtained immediately.
To minimize the possibility of catalytic converter damage:
•
Do not interrupt the ignition when the transmission is in
gear and the vehicle is in motion.
• Do not try to start the vehicle by pushing or towing the
vehicle.
• Do not idle the engine with any ignition components
disconnected or removed, such as when diagnostic
testing, or for prolonged periods during very rough idle
or malfunctioning operating conditions.
8
SERVICING AND MAINTENANCE 381
Disposal Of Used Coolant
Used ethylene glycol-based coolant (antifreeze) is a regu-
lated substance requiring proper disposal. Check with your
local authorities to determine the disposal rules for your
community. To prevent ingestion by animals or children,
do not store ethylene glycol-based coolant in open contain-
ers or allow it to remain in puddles on the ground. If
ingested by a child or pet, seek emergency assistance
immediately. Clean up any ground spills immediately.
Checking Coolant Level — 6.4L Engine
The level of the coolant in the pressurized coolant bottle
should be between the “MIN” and “MAX” range on the
bottle when the engine is cold.
The radiator normally remains completely full, so there is
no need to remove the cap unless checking for coolant
freeze point or replacing engine coolant (antifreeze). Ad-
vise your service attendant of this. As long as the engine
operating temperature is satisfactory, the coolant bottle
need only be checked once a month. When additional
engine coolant (antifreeze) is needed to maintain the
proper level, it should be added to the coolant bottle. Do
not overfill.
Points To Remember
NOTE:When the vehicle is stopped after a few miles/
kilometers of operation, you may observe vapor coming
from the front of the engine compartment. This is normally
a result of moisture from rain, snow, or high humidity
accumulating on the radiator and being vaporized when
the thermostat opens, allowing hot engine coolant (anti-
freeze) to enter the radiator.
If an examination of your engine compartment shows no
evidence of radiator or hose leaks, the vehicle may be
safely driven. The vapor will soon dissipate.
• Do not overfill the coolant expansion bottle.
• Check the coolant freeze point in the radiator and in the
coolant expansion bottle. If engine coolant (antifreeze)
needs to be added, the contents of the coolant expansion
bottle must also be protected against freezing.
• If frequent engine coolant (antifreeze) additions are
required, the cooling system should be pressure tested
for leaks.
8
SERVICING AND MAINTENANCE 385
•Maintain engine coolant (antifreeze) concentration at a
minimum of 50% OAT coolant (conforming to
MS.90032) and distilled water for proper corrosion pro-
tection of your engine which contains aluminum com-
ponents.
• Make sure that the coolant expansion bottle overflow
hoses are not kinked or obstructed.
• Keep the front of the radiator clean. If your vehicle is
equipped with air conditioning, keep the front of the
condenser clean.
• Do not change the thermostat for Summer or Winter
operation. If replacement is ever necessary, install ONLY
the correct type thermostat. Other designs may result in
unsatisfactory engine coolant (antifreeze) performance,
poor gas mileage, and increased emissions.
Brake System
In order to assure brake system performance, all brake
system components should be inspected periodically. Refer
to the “Maintenance Plan” in this section for the proper
maintenance intervals.
WARNING!
Riding the brakes can lead to brake failure and possi-
bly a collision. Driving with your foot resting or riding
on the brake pedal can result in abnormally high brake
temperatures, excessive lining wear, and possible
brake damage. You would not have your full braking
capacity in an emergency.
Fluid Level Check — Brake Master Cylinder
The fluid level of the master cylinder should be checked
when performing under the hood service or immediately if
the brake system warning lamp indicates system failure.
The brake master cylinder has a translucent plastic reser-
voir. On the outboard side of the reservoir, there is a
“MAX” mark and a “MIN” mark. The fluid level must be
kept within these two marks. Do not add fluid above the
MAX mark because leakage may occur at the cap.
With disc brakes the fluid level can be expected to fall as
the brake linings wear. However, an unexpected drop in
fluid level may be caused by a leak and a system check
should be conducted.
386 SERVICING AND MAINTENANCE
CAUTION!
Using a transmission fluid other than the manufactur-
er ’s recommended fluid may cause deterioration in
transmission shift quality and/or torque converter
shudder, and will require more frequent fluid and
filter changes. Refer to “Fluids And Lubricants” in
“Technical Specifications” for fluid specifications.
Special Additives
The manufacturer strongly recommends against using any
special additives in the transmission. Automatic Transmis-
sion Fluid (ATF) is an engineered product and its perfor-
mance may be impaired by supplemental additives. There-
fore, do not add any fluid additives to the transmission.
The only exception to this policy is the use of special dyes
for diagnosing fluid leaks. Avoid using transmission seal-
ers as they may adversely affect seals.
CAUTION!
Do not use chemical flushes in your transmission as
the chemicals can damage your transmission compo-
nents. Such damage is not covered by the New Vehicle
Limited Warranty.
Fluid Level Check
Check the fluid level when the engine is fully warmed up
and the transmission fluid is at normal operating tempera-
ture. Driving with an improper fluid level will greatly
reduce the life of the transmission and of the fluid. Check
the fluid level whenever the vehicle is serviced.
Fluid Level Check — Procedure
It is best to check the fluid level when the transmission is at
normal operating temperature (170-180°F / 77-82°C for 66RFE
transmission, or 158–176°F / 70–80°C for AS66RC transmis-
sion). This normally occurs after at least 15 miles (25 km) of
driving. At normal operating temperature the fluid cannot be
held comfortably between the fingertips. You can read the
transmission sump temperature in the instrument cluster dis-
play (refer toInstrument Cluster Display” in “Getting To
Know Your Instrument Panel” for further information).
Use the following procedure to check the transmission
fluid level properly:
1. Monitor the transmission temperature using the instru- ment cluster display, and operate the vehicle as required
to reach the normal operating temperature. If the trans-
mission is not functioning properly, or the vehicle
cannot be driven, see the NOTE and CAUTION below
about checking the fluid level at colder temperatures.
388 SERVICING AND MAINTENANCE
2. Park the vehicle on level ground.
3. Run the engine at normal idle speed for at least 60seconds, and leave the engine running for the rest of this
procedure.
4. Fully apply the parking brake and press the brake pedal.
5. Place the gear selector momentarily into each gear position (allowing time for the transmission to fully
engage in each position), ending with the transmission
in PARK.
6. Wipe the area around the dipstick clean to prevent dirt from entering the transmission.
7. Remove the dipstick, wipe it clean and reinsert it until seated.
8. Remove the dipstick again and note the fluid level on both sides. The fluid level reading is only valid if there
is a solid coating of oil on both sides of the dipstick.
Note that the holes in the dipstick will be full of fluid if
the actual level is at or above the hole. The fluid level
should be between the “HOT” (upper) reference holes
on the dipstick at normal operating temperature. If the
fluid level is low, add fluid through the dipstick tube to
bring it to the proper level. Do not overfill.Use ONLY the specified fluid (see
Fluids, Lubricants, and Genuine
Parts for fluid specifications). After adding any quan-
tity of oil through the dipstick tube, wait a minimum of
two minutes for the oil to fully drain into the transmis-
sion before rechecking the fluid level.
NOTE: If it is necessary to check the transmission below
the operating temperature, the fluid level should be be-
tween the two “COLD” (lower) holes on the dipstick with
the fluid at 60-70°F / 16-21°C for 66RFE transmission, or
68-86°F / 20-30°C for AS66RC transmission. Only use the
COLD region of the dipstick as a rough reference when
setting the fluid level after a transmission service or fluid
change. Re-check the fluid level, and adjust as required,
once the transmission reaches normal operating tempera-
ture.
CAUTION!
If the fluid temperature is below 50°F (10°C) it may not
register on the dipstick. Do not add fluid until the
temperature is elevated enough to produce an accurate
reading. Run the engine at idle, in PARK, to warm the
fluid.
8
SERVICING AND MAINTENANCE 389
9. Reinsert the dipstick. Check for leaks. Release the park-ing brake.
NOTE: To prevent dirt and water from entering the trans-
mission after checking or replenishing fluid, make sure that
the dipstick cap is properly reseated. It is normal for the
dipstick cap to spring back slightly from its fully seated
position, as long as its seal remains engaged in the dipstick
tube.
Fluid And Filter Changes
Refer to the “Maintenance Plan” for the proper mainte-
nance intervals.
In addition, change the fluid and filters if the fluid becomes
contaminated (with water, etc.), or if the transmission is
disassembled for any reason.
Rear Axle And 4x4 Front Driving Axle Fluid Level
For models with 9.25 in Front Axles and 11.5 in Rear Axles,
refer to “Fluids And Lubricants” in “Servicing And Main-
tenance” for further information. For normal service, peri-
odic fluid level checks are not required. When the vehicle is
serviced for other reasons, the exterior surfaces of the axle
assembly should be inspected. When checking the fluid level (4500/5500 only), the vehicle
should be in a level position. The fluid level should be ¼ in
± ¼ in (6.4 mm ± 6.4 mm) below the fill hole on the front
axle. The fluid level should be level with the bottom of the
fill hole on the rear axle.
Drain And Refill
On 4500/5500 vehicles, remove the lower bolt to drain the
axle fluid.
4500/5500 Rear Axle Plugs
1 — 4500/5500 Rear Axle Fluid Fill Plug
2 — 4500/5500 Rear Axle Fluid Drain Plug
390 SERVICING AND MAINTENANCE
Refer to “Scheduled Servicing” in this chapter for the
proper maintenance intervals.
Lubricant Selection
Refer to “Fluids And Lubricants” in “Technical Specifica-
tions” for further information.
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 Differentials DO NOT REQUIRE any lim-
ited slip oil additive (friction modifiers).
NOTE: Slight noise and mild shuddering may be evident
while turning a vehicle with limited slip differential on
concrete or dry pavement. These conditions should be
considered normal operation of the limited slip differential.
Transfer Case
Selection Of Lubricant
Use only the manufacturer’s recommended fluid. Refer to
“Fluids And Lubricants” in “Technical Specifications” for
further information.
Fluid Level Check
This fluid level can be checked by removing the filler plug.
The fluid level should be to the bottom edge of the filler
plug hole with the vehicle in a level position.
Drain And Refill
Refer to the “Maintenance Plan” for the proper mainte-
nance intervals.
HOISTING
A conventional floor jack may be used at the jacking
locations. Refer to the graphics that show jacking locations.
However, a floor jack or frame hoist must never be used on
any other parts of the underbody.
CAUTION!
Never use a floor jack directly under the differential
housing of a loaded truck or damage to your vehicle
may result.
8
SERVICING AND MAINTENANCE 391
TIRES
Tire Safety Information
Tire safety information will cover aspects of the following
information: Tire Markings, Tire Identification Numbers,
Tire Terminology and Definitions, Tire Pressures, and Tire
Loading.
Tire Markings
Tire Markings
1 — U.S. DOT Safety
Standards Code (TIN)4 — Maximum Load
2 — Size Designation 5 — Maximum Pressure
3 — Service Description 6 — Treadwear, Traction and Temperature Grades
392 SERVICING AND MAINTENANCE