If either the front or rear hydraulic system loses normal
braking capability, the remaining system will still function
with some loss of overall braking effectiveness. This will be
evident by increased pedal travel during application,
greater pedal force required to slow or stop, and activation
of the “Brake Warning Light” and the “ABS Warning
Light” (if equipped) during brake use.
The brake system power assist is provided by a hydro-
boost unit which shares fluid with the power steering
system. You may experience some clicking or hissing
noises from the hydro-boost system during hard braking
conditions.
NOTE:Under cold temperatures, pedal effort will be
higher than normal until the power steering fluid reaches
operating temperature.
Hydraulic Brake Assist
The brake system power assist is provided by a hydro-
boost unit which shares fluid with the power steering
system. You may experience some clicking or hissing
noises from the hydro-boost system during hard braking
conditions. NOTE:
Under cold temperatures, pedal effort will be
higher than normal until the power steering fluid reaches
operating temperature.
ELECTRONIC BRAKE CONTROL SYSTEM
Your vehicle is equipped with an advanced Electronic
Brake Control system (EBC). This system includes Elec-
tronic Brake Force Distribution (EBD), Anti-Lock Brake
System (ABS), Brake Assist System (BAS), Hill Start Assist
(HSA), Traction Control System (TCS), Electronic Stability
Control (ESC), and Electronic Roll Mitigation (ERM). These
systems work together to enhance both vehicle stability
and control in various driving conditions.
Your vehicle may also be equipped with Trailer Sway
Control (TSC) and Hill Descent Control (HDC).
Electronic Brake Force Distribution (EBD)
This function manages the distribution of the braking
torque between the front and rear axles by limiting braking
pressure to the rear axle. This is done to prevent overslip of
the rear wheels to avoid vehicle instability, and to prevent
the rear axle from entering ABS before the front axle.
5
STARTING AND OPERATING 357
Tire Size
The tire size on the Vehicle Certification Label represents
the actual tire size on your vehicle. Replacement tires must
be equal to the load capacity of this tire size.
Rim Size
This is the rim size that is appropriate for the tire size
listed.
Inflation Pressure
This is the cold tire inflation pressure for your vehicle for
all loading conditions up to full GAWR.
Curb Weight
The curb weight of a vehicle is defined as the total weight
of the vehicle with all fluids, including vehicle fuel, at full
capacity conditions, and with no occupants or cargo loaded
into the vehicle. The front and rear curb weight values are
determined by weighing your vehicle on a commercial
scale before any occupants or cargo are added.
Loading
The actual total weight and the weight of the front and rear
of your vehicle at the ground can best be determined by
weighing it when it is loaded and ready for operation.The entire vehicle should first be weighed on a commercial
scale to insure that the GVWR has not been exceeded. The
weight on the front and rear of the vehicle should then be
determined separately to be sure that the load is properly
distributed over the front and rear axle. Weighing the
vehicle may show that the GAWR of either the front or rear
axles has been exceeded but the total load is within the
specified GVWR. If so, weight must be shifted from front to
rear or rear to front as appropriate until the specified
weight limitations are met. Store the heavier items down
low and be sure that the weight is distributed equally. Stow
all loose items securely before driving.
Improper weight distributions can have an adverse effect
on the way your vehicle steers and handles and the way
the brakes operate.
CAUTION!
Do not load your vehicle any heavier than the GVWR
or the maximum front and rear GAWR. If you do, parts
on your vehicle can break, or it can change the way
your vehicle handles. This could cause you to lose
control. Also overloading can shorten the life of your
vehicle.
408 STARTING AND OPERATING
Towing Condition Wheels OFF TheGroundTwo-Wheel
Drive Models Four-Wheel Drive Models
Dolly Tow Front NOT
ALLOWED NOT ALLOWED
Rear OK NOT ALLOWED
On Trailer ALLOK OK
NOTE: When towing your vehicle, always follow applicable state and provincial laws. Contact state and provincial Highway Safety offices for additional details.
Recreational Towing — Two-Wheel Drive Models
DO NOT flat tow this vehicle. Damage to the drivetrain
will result.
Recreational towing (for two-wheel drive models) is al-
lowedONLY if the rear wheels are OFFthe ground. This
may be accomplished using a tow dolly or vehicle trailer. If
using a tow dolly, follow this procedure:
1. Properly secure the dolly to the tow vehicle, following the dolly manufacturer’s instructions.
2. Drive the rear wheels onto the tow dolly.
3. Firmly apply the parking brake. Place automatic trans- mission in PARK, manual transmission in gear (not in
NEUTRAL). 4. Properly secure the rear wheels to the dolly, following
the dolly manufacturer’s instructions.
5. Turn the ignition OFF and remove the key fob.
6. Install a suitable clamping device, designed for towing, to secure the front wheels in the straight position.
CAUTION!
•Towing with the rear wheels on the ground will
cause severe transmission damage. Damage from
improper towing is not covered under the New
Vehicle Limited Warranty.
• Do not disconnect the driveshaft because fluid may
leak from the transmission, causing damage to inter-
nal parts.
424 STARTING AND OPERATING
MAINTAINING YOUR VEHICLE
CONTENTS
ENGINE COMPARTMENT — 6.4L ...........453
ONBOARD DIAGNOSTIC SYSTEM (OBD II) . . . .454
▫ Onboard Diagnostic System (OBD II)
Cybersecurity ........................ .454
▫ Loose Fuel Filler Cap Message .............455
EMISSIONS INSPECTION AND MAINTENANCE
PROGRAMS .......................... .455
REPLACEMENT PARTS ...................456
DEALER SERVICE ...................... .456
MAINTENANCE PROCEDURES .............457
▫ Engine Oil .......................... .457
▫ Engine Oil Filter ...................... .459
▫ Engine Air Cleaner Filter .................460
▫ Accessory Drive Belt Inspection ............462
▫ Maintenance-Free Battery .................463 ▫
Air Conditioner Maintenance ..............464
▫ Front Prop Shaft Lubrication — Four-Wheel Drive
Models ............................. .470
▫ Body Lubrication ..................... .471
▫ Windshield Wiper Blades .................471
▫ Adding Washer Fluid ...................474
▫ Exhaust System ....................... .475
▫ Cooling System ....................... .476
▫ Brake System ........................ .481
▫ Rear Axle And 4x4 Front Driving Axle Fluid
Level .............................. .482
▫ Transfer Case ........................ .483
▫ Automatic Transmission — If Equipped ......484
▫ Appearance Care And Protection From
Corrosion ........................... .486
7
ENGINE COMPARTMENT — 6.4L
1 — Coolant Pressure Bottle6 — Battery
2 — Transmission Dipstick 7 — Power Distribution Center (Fuses)
3 — Engine Oil Fill 8 — Washer Solvent
4 — Engine Oil Dipstick 9 — Power Steering Fluid Reservoir
5 — Brake Fluid Reservoir 10 — Air Cleaner Filter
7
MAINTAINING YOUR VEHICLE 453
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 Schedule” 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.
Brake Fluid Level Check
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.
Use only the manufacturer’s recommended brake fluid.
Refer to “Fluids, Lubricants, And Genuine Parts” in “Main-
taining Your Vehicle” for further information.
WARNING!
•
Use only manufacturer’s recommended brake fluid.
Refer to “Fluids, Lubricants, And Genuine Parts” in
“Maintaining Your Vehicle” for further information.
Using the wrong type of brake fluid can severely
damage your brake system and/or impair its perfor-
mance. The proper type of brake fluid for your
vehicle is also identified on the original factory
installed hydraulic master cylinder reservoir.
(Continued)
7
MAINTAINING YOUR VEHICLE 481
WARNING!(Continued)
•To avoid contamination from foreign matter or mois-
ture, use only new brake fluid or fluid that has been
in a tightly closed container. Keep the master cylin-
der reservoir cap secured at all times. Brake fluid in
a open container absorbs moisture from the air
resulting in a lower boiling point. This may cause it
to boil unexpectedly during hard or prolonged brak-
ing, resulting in sudden brake failure. This could
result in a collision.
• Overfilling the brake fluid reservoir can result in
spilling brake fluid on hot engine parts, causing the
brake fluid to catch fire. Brake fluid can also damage
painted and vinyl surfaces, care should be taken to
avoid its contact with these surfaces.
• Do not allow petroleum based fluid to contaminate
the brake fluid. Brake seal components could be
damaged, causing partial or complete brake failure.
This could result in a collision.
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, Lubricants, And Genuine Parts” in “Main-
taining Your Vehicle” for further information. For normal
service, periodic 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.
482 MAINTAINING YOUR VEHICLE
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
transmission). 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 display (refer toInstrument Cluster
Display” in “Understanding 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.
2. Park the vehicle on level ground.
3. Run the engine at normal idle speed for at least 60 seconds, 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.
7
MAINTAINING YOUR VEHICLE 485