Driver-controlled differential lock
To prevent the vehicle from moving when servicing the wheels, tires or
brakes, turn the engine off and raise all drive wheels of the locker
differential axle. Axles equipped with NoSPIN Detroit Locker differentials
deliver power to both wheels even when only one wheel is on the ground.
Failure to raise all drive wheels with this type of differential
could cause the vehicle to move unexpectedly, resulting in
property damage, personal injury or death.
Care should be taken to avoid sudden accelerations when both drive
wheels are on a slippery surface.
Sudden accelerations on slippery surfaces could cause the
wheels to spin, the vehicle to turn sideways on a crowned road
surface or in a turn, possibly resulting in loss of vehicle control and
personal injury.
Some Dana/Spicer drive axles have a driver-controlled differential lock.
The differential lock can lock or unlock the differential when the vehicle
is moving or stopped. When extra traction is required, the differential
lock will provide full power to both axles.
The differential can be locked or unlocked when the vehicle is moving at
a constant speed of less than 40 km/h (25 mph) and while the wheels
are not slipping. If the differential is locked and vehicle speed exceeds
40 km/h (25 mph), the differential will automatically unlock. Also, the
differential must not be locked when the vehicle is traveling down steep
grades and traction is minimal.
When the differential is locked, the vehicle’s turning radius will increase
(vehicle will“under-steer”)
Axle conversions
It is not recommended, or approved, for axle conversions to be
performed. However, it is understood that, on occasion, aftermarket
add-on axles are installed by others on the truck chassis which allow
operator control for weight transfer from other axles (i.e., air lift axles).
When operating a loaded vehicle, the driver must keep all
adjustable axles on the ground at all times, supporting their
share of the vehicle’s load. Failure to do so can overload other axles,
tires, wheels, springs, steering components, brakes and frames,
resulting in early component failure, loss of vehicle control, possible
property damage and personal injury.
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Check to make sure that the axle mounting U-bolt nuts, attaching or
mounting bolts and nuts are securely tightened. Regularly check front
axle for damage, binding, worn parts and adequate lubrication.
At regular intervals, or during other scheduled maintenance, (tire
rotation/service, wheel bearing service, alignment, etc.) the kingpins
should be checked for excessive wear. Refer to the service manual for
proper procedures.
Toe-in setting - general inspection
Inspecting steer axle tires in the first 4,800–16,000 service km
(3,000–10,000 service miles) will generally show if tires are wearing
normally.
Rapid outside shoulder wear on both tires indicates too much toe-in.
Rapid inside shoulder wear on both tires indicates too much toe-out. In
P&D-type service, which includes school buses, left-to-right steer tire
tread life differentials up to 40% can be observed depending on routes
and other variables.
Follow the tire manufacturer’s recommended cold inflation pressure for
the tire size, load range (ply rating) and steer axle loading typical for
their operation (each steer axle tire will equal
1⁄2steer axle loading).
Special applications may warrant a setting based on past experience with
the type of tire operating loads and conditions. Radial tires are more
sensitive to toe-in setting than bias ply tires. While not insensitive to
vehicle alignment, fine tuning school bus alignment to line-haul truck
standards will not drastically improve tire tread life.
It is essential that correct toe-in and tire pressure be maintained for
optimum tire wear.
Rear axle - general inspection
Check to make sure that the axle mounting U-bolts, attaching or
mounting bolts and nuts are securely tightened. Refer toU-bolt nut
torque chartin this chapter. Regularly check the rear axle for damaged,
binding or worn parts.
NoSpin Detroit Locker positive locking differential
Vehicle equipped with this type differential have the operator’s manual
supplied with the vehicle. Refer to this manual for maintenance checks.
Brake system - general inspection
Your vehicle is equipped with non-asbestos brake linings. However,
exposure to excessive amounts of brake material (whether asbestos or
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interval to determine if adjustment is necessary. Brake chamber push
rods on original equipment chambers now incorporate a stroke indicator
to aid in adjustment checks; an orange paint marker near the base of the
push rod. If the push rod is clean and the brakes require adjustment, the
orange marker can be seen protruding from the chamber when the
brakes are applied.
Slack adjusters should also be checked to ensure proper operation of the
adjuster mechanism at the six-month interval. Push rod travel should be
kept at a minimum without the brakes dragging.
Inspect the brake lining every maintenance interval. When brake lining or
blocks are worn to within 1.6 mm (1/16 in.) of rivets, brake lining must
be replaced. This inspection or adjustment should only be performed by
a qualified technician and must be in accordance with instructions
provided by the service manual.
Do not back off or disconnect the front brakes so that they are less
effective, letting the rear brakes do all the stopping of the vehicle. Do
not overlook the brakes on the trailer, either. Brake condition on the
trailer is just as important as the tractor. Proper brake balance on trucks
and tractor-trailers is essential for effective braking.
Once a year, the entire brake system must be inspected. Check the
following:
•Any rubber as it may deteriorate whenever used. Rubber brake
components should be inspected by a qualified technician and
replaced as necessary. Replacement intervals vary according to the
severity and length of vehicle service.
•Condition of brake drums, brake chambers and slack adjusters.
•System for air leaks.
•Hose or pipes for rust, damage and deterioration.
•Operation of service and parking brakes.
Some parts such as air brake chamber diaphragm, air compressor and air
cleaner should be inspected periodically and replaced if considered
unserviceable.
Air brakes - air dryer
Performance of desiccant or after-cooler type air dryers is dependent on
climatic conditions in which your vehicle is operating. Maintenance
schedules must be establishes for each specific operation.
The use of an air dryer on a vehicle does not eliminate the need to
periodically drain the air reservoirs.
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Prior to re-installing rear aluminum hub-piloted wheels, clean each wheel
locator pad on the hub from all dirt, rust and foreign material. Apply a
light coat of chassis grease, never-seize or disc brake corrosion control
grease, only to the wheel locator pad.
When installing the tire and rim assembly on disc-brake equipped axles,
make sure the tire valve stem clears the brake caliper. The use of a tire
manufacturer’s stem forming tool is the only acceptable method of
obtaining clearance when necessary.
Note:Always observe the following instructions:
•Always loosen rim clamps before complete removal of nut from stud
(cast spoke wheels). With loosened nuts on stud, strike clamps with a
heavy hammer and be sure each clamp is loose.
•Always deflate tires completely before removing locks or side rings.
•Always inflate tires in a safety cage.
•Never mix rim side rings or lock rings of different types,
manufacturers or sizes.
•Never use cracked, bent or badly rusted parts.
•Never re-inflate flat tires on-vehicle; use the spare tire.
•Never add air until each side ring or lock ring is fully seated.
•Never hammer side ring or lock ring on a partially- or fully-inflated
tire.
Failure to follow these instructions could result in property
damage, personal injury or death
Proper torque
It is important to tighten and maintain wheel and rim mounting nuts to
the proper torque. Loose nuts or over-tightened nuts can lead to
premature wear and possible failure of the wheel and/or mounting
hardware.
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LUBRICATION AND MAINTENANCE INTERVALS
New vehicles are lubricated at the factory. After the vehicle is placed in
operation, regular lubrication intervals, based on the type of service and
road conditions, should be established. Thorough lubrication at the
specified intervals will insure outstanding life cycle value and will reduce
overall expense.
The lubrication intervals specified should be performed at whatever
interval occurs first, whether it is months, kilometer (miles) or hours.
Only lubricants of superior quality, such as Motorcraft lubricants, should
be used. The use of inferior products will reduce the service life of the
vehicle or result in failure of its components.
Unless otherwise specified, never add lubricant unless it is the same
grade as that which is already being used. If the grade is not known or
not available, drain, flush and refill with new lubricant.
The interval between lubrication periods, oil changes, etc. depends
entirely upon operating conditions. The loads carried, speeds, road and
weather conditions all contribute to the frequency of lubrication periods.
In some types of operation, and where operating conditions are
extremely severe (such as in deep water, mud or unusually dusty
conditions), the vehicle may require lubrication after every 24 hours of
operation.
Maintenance intervals
Maintenance intervals are provided for three types of general vehicle
environments: On-Highway, City and Severe Service. In all applications,
the actual interval is determined by monitoring kilometers (miles) and
time and when the engine is due for an oil change. When the engine oil
change is required prior to the truck lubrication interval, it is
recommended that the lubrication be performed at the same time in
order to reduce your vehicle’s time out of service.
•On-Highway:96,000 km (60,000 miles) or more annually.
•City:95,000 km (59,000 miles) or less annually.
•Severe Service:32,000 km (20,000 miles) or less annually on/off
road in dirty conditions.
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Check every oil
changeOil change
intervals are as follows:
Power Stroke - 10,000 ;
Caterpillar - 15,000 ;
Cummins - 15,000
(refer to the Caterpillar
and Cummins service
manuals for further
instructions and
information)Engine system
Check the engine cooling system - hoses, clamps and protection
Inspect the drive belts
Exhaust system
Inspect the entire exhaust system (including the inlet pipe(s),
muffler(s), outlet pipe(s), clamps and fasteners) for holes,
leakage, breakage, corrosive damage and separation from other
components. Adjust, service or replace with the same or the
equivalent part. (Also a noise emission control service)
Suspension system
Lubricate the front and rear spring pins
Tighten the front and rear spring U-bolts to the specified torque
Driveline and rear axle system
Lubricate the U-joints and the slip yoke
Brake system
Lube the air brake foot control valve, hinge and roller
Inspect the drum brake linings through the inspection holes
Lubricate the brake camshafts (air brakes)
Lubricate the brake slack adjuster (air brakes)
Lubricate rear caliper slide rails
Inspect the disc brake pads and the piston boots (hydraulic
brakes)
Clutch system
Lubricate the clutch release cross shaft and all linkages
Check the clutch fluid
Fuel system
Drain the accumulated water or sediment from the fuel tank(s)
Steering system
Lubricate the steering shaft(s), U-joints and splines when
equipped with grease fittings
Lubricate the front axle spindle pins
Lubricate the steering linkage when equipped with grease fittings
Grease the power steering gear output shaft
* Coolant protection checks should be made just prior to the onset of freezing weather,
where applicable. If coolant is dirty or rusty in appearance, the system should be drained,
flushed and refilled with the prescribed solution of cooling system fluid and water. Use only
permanent type coolant that meets Ford specifications WSS-M97B51-A1. See the engine
manufacturer’s operating guide for supplemental corrosion inhibitor specifications.
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