tank for connection to an outside air supply. The valve permits the
system to be recharged with air from an outside source, releasing the
spring-actuated parking brakes. The vehicle may then be towed in an
emergency.
An outside air source can be used only if the protected system is in
operating condition. If air pressure cannot be restored in the protected
air system, the spring-actuated brakes must be released manually.
Releasing spring brake manually
Do not attempt to disassemble the parking brake chamber under
any circumstances. The high spring load may cause serious
injury if the chamber clamps are removed.
If air pressure is released from the spring brake chamber the power
spring applies the brake and, unless air pressure can be re-established,
the spring brake must be released as follows in order to move the
vehicle.
Block the wheels to prevent the vehicle from moving.
Unexpected and possibly sudden vehicle movement may occur if
these precautions are not taken.
Impact wrenches should not be used as they may damage the piston and
prevent proper caging of the spring. Do not apply more than 68 Nm (50
lb-ft) torque to the release bolt nut.
1. Remove the stud tool and nut
from the carrying pocket on the
brake chamber assembly.
2. Remove the access plug from the
end of the spring chamber.
3. Insert the release stud through
the opening in the chamber and into
the spring pressure plate.
Driving
123
Air suspension dump valve
The dump valve switch activates the
dump valve. The dump valve
releases air from the air springs and
lowers the rear suspension, allowing
you to back under a low trailer
when necessary.
DRIVING WITH AN AUTOMATIC TRANSMISSION (IF EQUIPPED)
Allison automatic transmission
Do not allow your vehicle to coast in N (Neutral). Transmission
braking is not available in N (Neutral). Allowing the vehicle to
coast in N (Neutral) could result in loss of vehicle control and severe
transmission damage.
The Allison automatic transmissions are a torque converter type, full
power shifting and fully automatic. They also have the added flexibility
of manually selecting and holding in the lower drive ranges which permit
the drive selection of the most suitable gear range to match varying road
and load conditions. To prevent destructive overspeeding of the engine,
the hold feature is not infinite, resulting in upshifts from the hold range
to the next higher range at some speed above the no-load governed
speed of the engine.
Allison AT-545
These transmissions have no P (Park) position. Before leaving
the driver's seat, always shift into N (Neutral) and set the
parking brake. Shut off the engine and remove your ignition key.
Always use wheel chocks for hilly or off-road parking. Unexpected and
possibly sudden vehicle movement may occur if these precautions are
not taken.
This transmission provides four forward speeds and one reverse range.
Driving
132
When split shifting, the axle shift control must stay UP in the
HIGH range until after any transmission lever movement.
A 2±speed axle should NEVER be shifted on a downgrade.
To downshift the axle from HIGH to LOW range, either the ring gear has
to speed up by one-third, or the wheels have to slow down by one-third
to allow for synchronization. When you are on a down grade, the wheels
will not slow down, but will tend to speed up. As a result, the ring gear
must be accelerated to synchronize speeds. You are however limited in
doing so by your engine governed speed, and may not be able to reach
synchronization to allow the shift to take place. If the shift is not
completed , the axle will be in neither HIGH nor LOW range and all
driveline retardation will be lost.
Ratio extender use
Low End
A 2±speed axle can be used as a ratio-extender when split shifting is not
necessary. For low end use, just shift the axle into the LOW to start out,
and shift to HIGH when the extra torque is no longer needed.
Transmission (5-speed) 1st 1st 2nd 3rd 4th 5th 6th
2-speed Axle Axle
LowAxle High
High End
To use the 2±speed axle as a high end ratio-extender, stay in the LOW
range for normal upshifts and only shift the axle to HIGH on the freeway
for greater road speed.
Transmission (5-speed) 1st 2nd 3rd 4th 5th 6th
Speed
Axle
High 2-Speed Axle Low for Gradeability
DRIVING THROUGH WATER
Do not drive quickly through standing water, especially if the depth is
unknown. Traction or brake capability may be limited and if the ignition
system gets wet, your engine may stall. Water may also enter your
engine's air intake and severely damage your engine.
If driving through deep or standing water is unavoidable, proceed very
slowly. Never drive through water that is higher than the bottom of the
Driving
148
10. Reset the air filter restriction indicator.
11. Inspect the air induction system for loose fitting, damaged or missing
components and repair as necessary.
SERVICING YOUR WHEELS AND TIRES
Wheel assembly
Your vehicle is fitted with hub
piloted wheels and two-element
swiveling lug nuts (20 & 22 mm).
Do not use taper type wheels or ball
seat wheel nuts.
²Do not paint the mating face of the hub/drum.
²Do not paint the two-element swiveling lug nuts or wheel stud.
²Do not allow an excessive thickness of paint to build between the disc
wheel mounting surfaces.
²Do not install disc wheels where the paint has not fully cured.
²At wheel changes, ensure mounting faces are clean and free of rust,
dirt and excess paint.
If fasteners are needed, use only Ford recommended replacement parts.
²To maintain the desired
torque/tension relation between
nut body and flange, it is
necessary to use clean engine oil
meeting Ford specification
WSS-M2C153-G between nut body and flange. Lubricate the nut body
and flange any time a wheel is removed.
Maintenance and Specifications
215
The M20 & M22 wheel nuts are right-hand threads. Refer to the
following chart for approved wheel lug nut torque.
Wheel type Bolt size Wheel nut torque
10-hole disc 285.75
mm bolt circleM22 (22 by 1.5 mm) 610-677 Nm (450-500
lb-ft)
8-hole disc 19.5x6.75
mm bolt circleM20 (20 by 1.5 mm) 610-677 Nm (450-500
lb-ft)
The disc wheel nuts on your vehicle were tightened before delivery.
Recheck torque of nuts at 160 km (100 miles) and 800 km (500 miles) of
new vehicle operation or any time a wheel is removed. Reset to
recommended torque levels.
Tires are one of the weaker weight carrying components of the
vehicle. Do not overload the vehicle beyond safe load carrying
capacity.
Avoid hammering rim with steel hammers.
Never run the engine with one wheel off the ground.
Failure to retighten wheel lug nuts as required could allow the
wheel to come off while the vehicle is in motion, possibly causing
loss of vehicle control and collision. Loose wheel studs may also cause
shimmy and vibration.
Use of aftermarket wheel assemblies is not recommended; they
may be incompatible with your vehicle and may result in
equipment failure and possible injury. Replacement with used wheels is
not advised; they may have been treated harshly or have high mileage
and could fail without warning.
Maintenance and Specifications
216
Refer to the Ford Service Manual applicable to your vehicle for proper
tightening procedures and torque specifications.
Periodically check the oil level on oil filled front bearing hubs. If
necessary, add oil through the filler plug so the oil level is between the
ADD and FULL marks indicated on the hub. Do not overfill. Overfilling
can result in oil on brake linings.
Refer to your Scheduled Maintenance Guide for fluid level checks and
change intervals for the front hubs.
Your front hubs may be filled with an optional synthetic fluid which
allows use of the extended service intervals. A green colored filler plug
identifies use of the synthetic fluid.
Tire/wheel rim selection and inflation pressures
Tire Size, Load
Range (PR)Wheel Width
(in.) and TypeSingle Rear Axle: Max. Tire
and Wheel Capacity kg. (lb.)
kPa @ (psi) (cold) by Axle
Tubeless Type Radial Ply Front Rear
10R22.5 F (12) 7.50 10H
(I.S.O.)10 300 (4 671)
698 10019 280 (8 745)
698 100
10R22.5 G (14) 7.50 10H
(I.S.O.)10 300 (4 671)
698 10021 000 (9 525)
711 115
11R22.5 G (14) 8.25 10H
(I.S.O.)12 080 (5 478)
703 10522 520 (10 213)
703 105
245/70R19.5 6.75 8H (I.S.O.) 10 300 (4 671)
698 10019 280 (8 745)
698 100
11X20 (16) 7.50 10H
(I.S.O.)12 080 (5 478)
703 10522 520 (10 213)
703 105
MINOR TROUBLESHOOTING GUIDE
Diesel engine
For troubleshooting information, refer to the diesel engine operator's
manual.
If engine won't crank
For troubleshooting information, refer to the engine operator's manual.
Maintenance and Specifications
219
Maintenance Operation Frequency - Observation
Check the transmission and
engine mountings (*b)Hard shifting or excessive vibration
Check and adjust transmission
controls (*b)High effort to shift or noisy
transmission
Check fuel pump pressure Insufficient full-throttle power or
backfiring
Clean radiator cap seal. Clean
and inspect the cap surface on
the radiatorWhen the cap does not hold pressure
Check the battery terminals for
corrosionWhenever electrical power supply has
diminished
Tighten the wheel mounting
nuts to the specified torque.
Refer toServicing your
wheels and tiresRequired initially at 804 and 1 609 km
(500 and 1 000 miles). Perform again
at 804 and 1 609 km (500 and 1 000
mile) intervals after each tire
removal/replacement.
*a During maintenance and repair, protect the fuel tube and the hose
assemblies, the power steering lines, and the brake lines from the
external heat, the acids and the abrasion that could damage the lines.
*b Check for (free) linkage action and ensure that (return) spring
force is adequate to maintain pedal free play.
*c Adjust, repair or replace as required with the same or equivalent
parts.
General Maintenance Information
244