
To start forward, place the gearshift lever in LO gear and disengage the
clutch while slightly depressing the accelerator. Operate the clutch and
upshift through the shift pattern (up to 4th) as required by driving
conditions. To shift into the HI range from 4th gear (LO range), place
the range control button in the HI range, then shift to 5th gear. Upshift
through 8th. When downshifting, shift 8-7-6-5, depress the range control
button to LO, then move the gearshift lever to 4-3-2-1-LO as necessary.
Never move the gearshift lever to the LO position when the transmission
is in the HI range.
Use LO-LO only for adverse conditions by changing the Deep Reduction
Button to the IN/FORWARD position, while the range selector is in the
LO range and the gearshift lever is in the LO position. Do not pre-select
Deep Reduction.
To upshift from LO-LO to LO in the
same gearshift lever position, move
the Deep Reduction Button to the
OUT/REARWARD position and
immediately release the accelerator,
depress the clutch pedal once to
break torque, and re-engage clutch.
The transmission will shift from Deep Reduction to low range when
synchronous is reached, then accelerate.
To go backward
Reverse is obtained by putting the
gearshift lever in R (Reverse) and
the range control button in LO or HI
(Deep Reduction Button should be
in the OUT/REARWARD position).
27
3
6
2 LO
LO-LO
8
4
R R
R R
5 1
1
Neutral
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POWER TAKE-OFF (PTO) OPERATION
Vehicles equipped with an Allison automatic transmission (except
3000 Series applications and vehicles equipped with a Caterpillar
engine)
The PTO can be operated while the vehicle is standing or moving. To
engage the PTO, apply the brakes and shift to any gear other than N
(Neutral), then engage the PTO.
If engagement is prevented by the gear teeth not meshing properly,
release the brakes and allow the vehicle to creep slightly or shift the
selector to N (Neutral) and then back into gear. The PTO should never
be engaged by clashing the gear teeth as this may damage the PTO unit
and the transmission PTO drive gear teeth. This could result in further
damage to the transmission and PTO.
PTO operation with vehicle stationary
Stop the vehicle, idle the engine and set the parking brake. Make sure
the gear selector is in any forward drive range, then engage the PTO.
After the PTO is engaged, move the range selector to N (Neutral).
Increase the engine speed until the desired power take-off operation
speed is obtained. To disengage the PTO after operation with the vehicle
standing, release the throttle, allow the drive equipment to come to a
stop, and then disengage the PTO.
When the PTO is operated with the vehicle stationary, the
transmission must be placed in N (Neutral) with the parking
brake set. If the transmission is not in N (Neutral) and is equipped
with a remote throttle control, an increase in engine speed can
overpower the parking brake and cause the vehicle to move, possibly
resulting in personal and/or property damage.
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.
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are not slipping. The differential must not be locked when the vehicle is
traveling down steep grades and traction is minimal.
Note:Never use the differential lock at vehicle speeds above 25 mph (40
km/h).
Note:The driver-controlled differential lock function will vary with some
transmissions.
•Vehicles equipped with an Allison 3000 Series transmission:The
differential lock and differential lock light will automatically disengage
at speeds above 25 mph (40 km/h). The differential lock will remain
off until either the vehicle is restarted or the differential lock switch is
turned off then back on.
•Vehicles equipped with a 5–speed, 6–speed or 7–speed manual
transmission or a non-MD automatic transmission:The driver
must manually deactivate the differential lock if using it at speeds
above 25 mph (40 km/h).
•Vehicles equipped with a 10–speed transmission:The differential
lock can only be activated when in low range and it will only stay
activated until it is turned off or when the transmission is put into
high range. When active and shifted into high range, it will temporarily
deactivate (automatically) until low range is selected again.
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.
TWO-SPEED REAR AXLE (IF EQUIPPED)
A two-speed rear axle allows the driver to select a LO range for greater
pulling power and a HI range for greater road speed and fuel economy.
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.
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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), the 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.
Shifting the axle from HI to LO range - vehicle stopped
Place the transmission in N (Neutral), then press the upper part of the
switch.
LOW
2SPD
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•U.S.
•Canada
Under no circumstances should your vehicle be loaded in excess of the
GVWR or GAWR. It is the operator’s responsibility to ensure that neither
the axle capacities, spring capacities, tire capacities nor the vehicle rated
GVWR is exceeded. For tire capacities, refer toMaintenance and
Specificationschapter.
Unloaded or lightly loaded vehicles
The braking system has been designed to safely stop your vehicle when
fully loaded to its GVWR.
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When operating empty or lightly loaded, sudden or hard braking
may induce wheel lockup with loss of vehicle control and the
possibility of accident and serious injury, especially on wet or slippery
road surfaces.
TRAILER TOWING
Towing a trailer places an additional load on your vehicle’s engine,
transmission, axle, brakes, tires and suspension. Inspect these
components carefully prior to and after any towing operation.
Your vehicle’s load capacity is designated by weight, not by volume, so
you cannot necessarily use all available space when loading a vehicle.
2nd unit bodies are not included in maximum trailer weight ratings. The
weight of the additional “body” must be subtracted from the maximum
trailer weight.
Note:Do not exceed the GVWR or the GAWR specified on the
certification label.
Towing trailers beyond the maximum recommended gross trailer
weight exceeds the limit of the vehicle and could result in
engine damage, transmission damage, structural damage, loss of vehicle
control, vehicle rollover and personal injury.
Model Maximum
GVWR - lb.
(kg)Maximum
GCWR - lb.
(kg)*
F-650 Regular/Super/Crew Cab 26000 (11793) 40000 (18143)
F-750 Regular/Super/Crew Cab 30000 (13608) 45000 (20412)
F-750 Regular/Super/Crew Cab 33000 (14969) 60000 (27216)
* Figures shown are the maximum available for each model. Actual
ratings may be less, depending on your transmission. Check with your
sales consultant for the exact rating on your vehicle.
Preparing to tow
Use the proper equipment for towing a trailer and make sure it is
properly attached to your vehicle. See your dealer or a reliable trailer
dealer if you require assistance.
Hitches
Do not use hitches that clamp onto the vehicle’s bumper or attach to the
axle. You must distribute the load in your trailer so that 10–15% of the
total weight of the trailer is on the tongue.
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Safety chains
Always connect the trailer’s safety chains to the frame or hook retainers
of the vehicle hitch. To connect the trailer’s safety chains, cross the
chains under the trailer tongue and allow slack for turning corners.
If you use a rental trailer, follow the instructions that the rental agency
gives to you.
Do not attach safety chains to the bumper.
Trailer brakes
Electric brakes and manual, automatic or surge-type trailer brakes are
safe if installed properly and adjusted to the manufacturer’s
specifications. The trailer brakes must meet local and Federal
regulations.
Do not connect a trailer’s hydraulic brake system directly to your
vehicle’s brake system. Your vehicle may not have enough
braking power and your chances of having a collision greatly increase.
Trailer lamps
Trailer lamps are required on most towed vehicles. Your vehicle may be
equipped with one of two possible trailer wiring designs. Make sure all
running lights, brake lights, turn signals and hazard lights are working.
See your dealer or trailer rental agency for proper instructions and
equipment for hooking up trailer lamps.
Driving while you tow
When towing a trailer:
•Keep your speed no faster than 70 mph (112 km/h) during the first
500 miles (800 km) of towing a trailer, and don’t make full throttle
starts.
•Turn off the speed control. The speed control may shut off
automatically when you are towing on long, steep grades.
•Consult your local motor vehicle speed regulations for towing a trailer.
•To eliminate excessive transmission shifting, use a lower gear. This will
also assist in transmission cooling.
•Anticipate stops and brake gradually.
•Do not exceed the GCWR rating or transmission damage may occur.
Servicing after towing
If you tow a trailer for long distances, your vehicle will require more
frequent service intervals. Refer to yourScheduled Maintenance Guide
for more information.
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Before hook-up, make sure:
•The fifth wheel jaws are fully opened.
•The fifth wheel is fully tilted back to prevent body damage when the
tractor is backed under a trailer.
•The trailer wheels are blocked and the trailer spring brakes are
adjusted and applied. Never chase a trailer.
•The brake hoses and light cords are clear of the fifth wheel.
Hook-up
1. Back the tractor squarely under the trailer, engaging the fifth wheel
jaws on the kingpin. Always back-up slowly, making sure the trailer is
neither too high nor too low. Avoid backing under the trailer from an
angle.
2. Connect the service and emergency brake hoses and trailer light
connector. Refer toTractor-trailer connectionin this chapter, adhering
to the warning and using the three-point stance while connecting and
disconnecting the trailer.
3. Inspect the jaws of the fifth wheel to be sure they have fully closed on
the trailer kingpin and the trailer plate is resting securely on the fifth
wheel.
4. Be sure the coupler release lever is in the locked position.
5. Charge the trailer brake system. Set the trailer brakes, either with the
hand valve or tractor protection valve. Pull against the trailer for an
additional check of proper hook-up. Do not pull hard enough to damage
or strain the equipment.
6. Set the tractor parking brakes and fully raise the trailer landing gear.
Refer toBrakesin this chapter for proper operation of the parking brake
and trailer brakes.
7. Check the operation of all trailer lights and correct any lights that may
be faulty.
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