2008 FORD F750 clutch

PTO operation while vehicle is moving
After the PTO is engaged for driven vehicle operation, shift to the
desired range and drive the vehicle. The speed of the PTO, during this
period of operation, will always maintain direct relation to vehicle speed.
PTO speed will decrease in relation to vehicle (transmission output)
speed as shifts to a higher gear occur. When operating the PTO while the
vehicle is moving, the PTO may be disengaged whenever it is no longer
required. When there is no load on the PTO gear, it can be pulled out of
engagement.
Vehicles equipped with an Allison 3000 Series automatic
transmission
The PTO drive gear is engine driven and provides direct engine power.
The PTO can be operated when the vehicle is either stationary or
moving.
The PTO gear is in constant mesh with the drive gear in the torque
converter housing. A friction clutch or constant drive is used to transmit
power to the PTO.
Vehicles equipped with a Caterpillar engine
The PTO will only operate if the transmission is in N (Neutral). This
feature can be overridden by a special service tool; see your dealer or
service representative for more information.
Vehicles equipped with a manual transmission
Transmission-mounted PTO units are available for local installation on
your vehicle. See yourBody Builder’s Layout Bookfor restrictions on
use and installation of PTO units.
To engage the PTO unit, stop the vehicle and place the transmission in N
(Neutral). Depress the clutch and allow the gears to stop rotating, then
engage the PTO unit. The PTO can also be selected with the
transmission in gear as long as the clutch is depressed.
When operating the PTO with the vehicle stationary, first set the parking
brake (chock the wheels if the vehicle is on a hill or another uneven
surface).
REAR AXLE INFORMATION
Axle operating temperature normally will not exceed 100°F (38°C). If
the operating temperature exceeds 230°F (110°C), the rate of axle
lubrication oxidation will increase and shorten the life of the lubricant
2008 F-650/750(f67)
Supplement
USA(fus)
Driving
123

These ranges can also be used to provide additional steps between
transmission shifts when driving on steep grades and/or fuel economy
may be factors.
Note:Do not shift between ranges when the speed control is on.
Never shift a two-speed axle when descending a steep grade as
this may cause loss of vehicle control and result in personal injury.
Axle shifting
Manual transmissions:
•To downshift,select the next lower gear, release and depress the
accelerator pedal rapidly, or while holding the accelerator pedal down,
release and engage the clutch rapidly.Note:The clutch method is
recommended when driving at slower speeds.
•To upshift,keep the accelerator pedal down, select the next higher
gear, release the accelerator and pause until the axle upshifts.Note:
De-clutch for smoother axle upshifts when driving at slower speeds.
Automatic transmissions:
•Use LO range for when you drive
a fully loaded vehicle on a severe
grade or in congested traffic. To
activate LO range, press the
upper portion of the switch.
•Use HI range for all normal
driving conditions with a lightly
loaded or partially loaded vehicle.
To activate HI range, press the
lower portion of the switch.
Note:You cannot split-shift with an automatic transmission. Also,
downshifting above 40 mph (64 km/h) may result in transmission or axle
damage.
Shifting the axle from LO to HI range - vehicle stopped
Place the transmission in N (Neutral), then press the lower part of the
switch.
Shifting the axle from LO to HI range - vehicle moving
Accelerate to approximately 35 mph (56 km/h), press the lower part of
the switch while the transmission is in N (Neutral), then release and
apply the accelerator.
LOW
2SPD
2008 F-650/750(f67)
Supplement
USA(fus)
Driving
126

Shifting the axle from HI to LO range - vehicle stopped
Place the transmission in N (Neutral), then press the upper part of the
switch.
Note:Do not shift the axle to LO range with the vehicle in motion.
Split-shifting (combined axle and transmission shift - manual
transmissions only)
Split-shift sequence
Ratio
combination1234567891011
Transmission
gear1st 1st 2nd 2nd 3rd 3rd 4th 4th 5th 6th 6th
Axle range LO HI LO HI LO HI LO HI LO LO HI
To downshiftthe axle to a slower ratio and shift the transmission, shift
the transmission and move the control switch to the lower ratio before
the clutch is re-engaged.
To upshiftthe axle and shift the transmission, move the control switch
to a faster ratio and make the transmission shift in the usual manner.
Ratio extender use
Low End
A two-speed axle can be used as a ratio-extender when split shifting is
not necessary. For low end use, just shift the axle into LO to start out,
and shift to HI when the extra torque is no longer needed.
Transmission (5-speed) 1st 1st 2nd 3rd 4th 5th 6th
Two-speed axle Axle low Axle high
High End
To use the two-speed axle as a high end ratio-extender, stay in the LO
range for normal upshifts and only shift the axle to HI on the freeway for
greater road speed.
Transmission
(5-speed)1st 2nd 3rd 4th 5th 6th
Speed
Two-speed axle Low for gradeability Axle high
2008 F-650/750(f67)
Supplement
USA(fus)
Driving
127

Towing the vehicle with the rear wheels suspended
Note:To avoid damage to the cab roof or air deflector when towing the
vehicle backward (rear wheels suspended) the air deflector must be
removed.
Whenever possible, it is preferable to tow a disabled vehicle from the
rear by raising the rear of the chassis. When towing a vehicle with the
rear of the chassis suspended the front wheels must be locked in the
straight-ahead position.
Vehicles equipped with a manual transmission must have at least 1.0 pint
(0.5L) of transmission fluid drained from the case. This will prevent the
transmission fluid from entering the clutch housing and fluid saturating
the clutch discs. Make sure that the transmission fluid is replaced before
the vehicle is returned to service.
2008 F-650/750(f67)
Supplement
USA(fus)
Roadside Emergencies
149

GENERAL SERVICING GUIDELINES AND PRECAUTIONS
As with any machine, care should be taken to avoid being injured when
performing maintenance, repairs or system checks. Improper or
incomplete service could result in the vehicle not working properly
which, in turn, may result in personal injury or damage to the vehicle or
equipment. It is the operator’s responsibility to see that the vehicle
receives proper care and maintenance. If you have any questions about
performing some service, have the service done by a qualified technician.
Servicing guidelines
When servicing your vehicle, always:
•turn off the ignition unless the particular procedure calls for the
engine to be running.
•set the parking brake or chock the wheels.
•use support stands, not a jack, whenever you must be under a raised
vehicle.
•do not smoke.
•wear safety glasses for eye protection.
•operate the engine in a well-ventilated area
•do not work on the brakes or the clutch unless the proper precautions
are taken to avoid inhaling friction material dust.
•do not wear loose-fitting clothing, hanging jewelry, watches or rings.
•avoid contact with hot metal parts. Allow the hot components to cool
before working with, or around them.
Quality service parts are available through your dealer. If dealer parts are
not used, the owner must make sure that the parts that are being used
are equivalent quality to dealer parts.
The use of inferior parts can adversely affect the quality and
reliability of your vehicle which, in turn, can result in property
damage, personal injury or death.
Note:To avoid damage to the vehicle’s electrical components, disconnect
the positive (+) and negative (-) battery cables prior to electric welding.
Attach the welder ground cable as close as possible to the part being
welded. If it is necessary to weld close to an electrical component, it is
recommended that the electronic component be temporarily removed.
Follow the periodic lubrication procedures and regular inspection
intervals as outlined. Have your dealer or service center inspect your
2008 F-650/750(f67)
Supplement
USA(fus)
Maintenance and Specifications
160

If you drive in extremely hot climates:
•It is still necessary to maintain the coolant concentration
above 40%.
•NEVER decrease the coolant concentration below 40%.
•Engine coolant concentrations below 40% will decrease the
corrosion protection characteristics of the engine coolant and
may cause engine damage.
•Engine coolant concentrations below 40% will decrease the
freeze protection characteristics of the engine coolant and may
cause engine damage.
•If available, refer to the chart on the coolant container to
ensure the coolant concentration in your vehicle will provide
adequate protection at the temperatures in which you drive.
Vehicles driven year-round in non-extreme climates should use a 50/50
mixture of engine coolant and distilled water for optimum cooling system
and engine protection.
Fan clutches
Your vehicle’s cooling system is equipped with a viscous fan clutch.
•The fan clutch helps control cooling, increase performance, improve
fuel economy and reduce noise.
•The fan clutch is controlled by bimetallic spring sensors. Do not
tamper with these sensors as this may change their calibration or keep
the fan clutch from operating at all.
Stay clear of the fan/fan area while the engine is running or
possible personal injury may occur.
FUEL FILTER/WATER SEPARATOR
Do not drain water separator while engine is running. Fuel may
ignite if separator is drained while engine is running or vehicle is
moving.
The fuel filter/water separator removes any contaminated particles
and/or water from the fuel before the fuel enters the engine.
Refer to your engine operator’s manual for information on draining and
replacing the fuel filter.
2008 F-650/750(f67)
Supplement
USA(fus)
Maintenance and Specifications
174

Instrument cluster lamp(s) will
illuminate and/or flash when
operator assistance is required. In
addition, engine performance will
become increasingly limited above
Level 1.
At Levels 1 and 2, two courses of action may be taken by the operator to
facilitate filter regeneration:
1. The vehicle may be driven on the highway at highway speeds,
2. The operator may perform a parked regeneration by following the
steps inParked regeneration procedure (Cummins engine only).
At Level 3, performing a parked regeneration is the only available course
of action (short of professional servicing) available to the operator for
regenerating the filter. At Level 4, professional servicing is the only way
to regenerate the filter.
Parked regeneration procedure (Cummins engine only)
When performing the parked regeneration procedure, make
certain the vehicle is safely off roadway, and the exhaust system
is away from people, or any flammable materials, vapors, or structures.
Engine speed may increase during parked regeneration.
Note:Parked regeneration is only available when the DPF lamp on the
instrument cluster is illuminated (solid or flashing).
1. Bring the vehicle to a complete stop on level ground and safely off the
road with the exhaust system away from people, flammable materials,
vapors or structures.
2. If your vehicle is equipped with an automatic transmission and a
steering column shift lever, place transmission in P (Park). Otherwise,
place the transmission in N (Neutral).
3. Remove feet from the accelerator pedal and clutch pedal (if
equipped).
4. Set the parking brake.
5.Within 5 seconds of setting the parking brake,remove foot from
the service brake pedal.
2008 F-650/750(f67)
Supplement
USA(fus)
Maintenance and Specifications
183

When these steps are performed successfully in the order outlined above,
the DPF lamp will begin flashing at a rate of once every 10 seconds. The
engine speed may also increase slightly. To allow parked regeneration to
continue uninterrupted:
1. The vehicle must remain parked
2. The transmission must remain in P (Park) or N (Neutral) (as
previously described in Step 2).
3. The accelerator pedal, service brake pedal, and clutch pedal (if
equipped) must not be depressed
4. The parking brake must remain set
On average (depending on filter level and other factors), the process will
take 20–30 minutes to complete. The DPF lamp will turn off when the
process is complete. Repeat Steps 1–5, if parked regeneration is
interrupted.
To discontinue parked regeneration (Cummins engine only)
Depress any of the floor pedals to discontinue parked regeneration.
Diesel particulate filter maintenance and service
The DPF is designed to retain a relatively large amount of residual ash
and provide many miles and hours of maintenance-free operation. At
some point, generally beyond 150,000 miles (240,000 km) or 5,000 hours
of operation (whichever comes first), the DPF will require professional
cleaning to remove the accumulated ash
The exact number of miles or hours of operation will vary greatly
depending upon vehicle/engine loading and operating conditions, ash
content of the engine oil, and quality of the diesel fuel used in your
truck. Adhering to your engine manufacturer’s recommended oil and fuel
specifications will maximize the miles and hours of operation before a
DPF professional cleaning is required. Refer to your engine
manufacturer’s owner’s manual for more details regarding recommended
maintenance and service of your DPF.
Exhaust outlet assembly
The normal operating temperature of the exhaust system is very
high. Never work around or attempt to repair any part of the
exhaust system until it has cooled. Failure to follow these instructions
may result in personal injury.
2008 F-650/750(f67)
Supplement
USA(fus)
Maintenance and Specifications
184