
WARNING:Block the wheels to help prevent the vehicle from
moving.
WARNING:Unexpected and possibly sudden vehicle movement
may occur if these precautions are not taken.
Loosen the jam nut (1) and un-thread the adjustment rod (2) from the
chamber to reduce tension on the cable (3). Continue to un-thread the
adjustment rod all the way and remove it from the chamber. The nut and
shaft are metric.
AIR BRAKES (IF EQUIPPED)
General air brake information
After starting the engine, give the air compressor time to build up the air
pressure to 60 psi (414 kPa) before moving the vehicle.
WARNING:Do not drive or continue to drive if the low air
pressure buzzer is sounding or the brake warning light is lit. These
warnings indicate that air pressure is not to normal operating level.
Continued use of the vehicle could result in loss of braking ability.
WARNING:Avoid repeated light application of the brake pedal.
This depletes air pressure faster and could result in loss of
braking capability.
Driving
115
2012 F-650/750(f67)
Supplement, 2nd Printing
USA(fus)

Releasing spring brake manually
WARNING: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.
WARNING:Block the wheels to help prevent the vehicle from
moving.
WARNING: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 50 ft-lb
(68 N•m) 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.
4. Turn the release stud one-quarter
turn to engage the stud tangs with
the slot in the pressure plate. Keep
the stud engaged and install the nut
on the release stud.
5. Tighten the nut until the spring is
fully caged and the brakes are
released. Do not loosen or remove
the release stud and nut unless the brake chamber is completely
assembled and is securely clamped.
6. When the air pressure is restored, unscrew and remove the release
stud and install in the carrying pocket. Install the access plug.
Driving
120
2012 F-650/750(f67)
Supplement, 2nd Printing
USA(fus)

Actuation of trailer park (emergency) or tractor bobtail position
To actuate the trailer brakes only, pull out the trailer air supply knob (1).
The trailer brakes are now applied whether emergency or spring brakes
are used on the trailer.
This mode is also used when the tractor or truck with trailer is used
during bobtail operation.
ANTI-LOCK BRAKE SYSTEM (ABS)
Your vehicle is equipped with an anti-lock braking system (ABS). This
system helps you maintain steering control during emergency stops by
keeping the brakes from locking. Noise from the ABS pump motor and
brake pedal pulsation may be observed during ABS braking; any
pulsation or mechanical noise you may feel or hear is normal.
When hard braking is required, apply continuous force on the brake
pedal. Do not pump the brake pedal since this reduces the effectiveness
of the ABS and increases your vehicle’s stopping distance. The ABS
activates immediately, allowing you to retain steering control during hard
braking and on slippery surfaces. However, the ABS does not decrease
stopping distance.
ABS warning light
The
light in the instrument cluster momentarily illuminates when the
ignition is turned on. If the light does not illuminate during start up,
remains on after the vehicle reaches 5–10 mph (8–16 km/h), or flashes,
the ABS may be disabled and may need to be serviced.
Even when the ABS is disabled, normal braking is still effective. If
the
light illuminates with the parking brake released, have your
brake system serviced immediately.
1
2
Driving
127
2012 F-650/750(f67)
Supplement, 2nd Printing
USA(fus)

BRAKE-SHIFT INTERLOCK
Vehicles equipped with a gasoline engine have a brake-shift interlock
feature that prevents the gearshift lever from being moved from P (Park)
when the ignition is in the on position and the brake pedal is not pressed.
If you cannot move the gearshift lever out of P (Park) with the ignition
in the on position and the brake pedal pressed, it is possible that a fuse
has blown or the vehicle’s brake lamps are not operating properly. Refer
toFuses and relaysin theRoadside Emergencieschapter.
If the fuse is not blown and the brake lamps are working properly, the
following procedure will allow you to move the gearshift lever from P (Park):
1. Apply the parking brake, and turn
the engine off.
2. Remove the lower finish panel
below the steering column
3. Turn the key to on (position 4),
but do not start engine.
4. Pull back on the solenoid, and at
the same time, shift the
transmission into N (Neutral).
5. Start the vehicle.
See your authorized dealer as
soon as possible if this
procedure is used.
WARNING:Do not drive
your vehicle until you verify
that the brake lamps are working.
1
2
34
5
Driving
131
2012 F-650/750(f67)
Supplement, 2nd Printing
USA(fus)

several transmission upshifts and downshifts; during this learning
process, slightly firmer shifts may occur. After this learning process,
normal shift feel and shift scheduling will resume.
P (Park)
This position locks the transmission and prevents the rear wheels from
turning.
To put your vehicle in gear:
1. Start the engine
2. Press the brake pedal
3. Move the gearshift lever into the desired gear
To put your vehicle in P (Park):
1. Come to a complete stop
2. Move the gearshift lever and securely latch it in P (Park)
WARNING:Always set the parking brake fully and make sure
the gearshift is latched in P (Park). Turn the ignition to the off
position and remove the key whenever you leave your vehicle.
R (Reverse)
With the gearshift lever in R (Reverse), the vehicle will move backward.
Always come to a complete stop before shifting into and out of R
(Reverse).
N (Neutral)
With the gearshift lever in N (Neutral), the vehicle can be started and is
free to roll. Hold the brake pedal down while in this position.
D (Drive)
This is the normal driving position for the best fuel economy. This
position allows automatic upshifts and downshifts through gears one
through six.
4 (Fourth)
This position allows automatic upshifts and downshifts in gears one
through four.
2 (Second)
Use 2 (Second) to start-up on slippery roads or to provide additional
engine braking on downgrades.
Driving
133
2012 F-650/750(f67)
Supplement, 2nd Printing
USA(fus)

Allison 2500
This transmission is available with a column-mounted gearshift lever. The
gear positions are displayed on the RNDL in the instrument cluster.
WARNING: To avoid sudden, unexpected vehicle
movement and possible personal injury or death:
1. Bring the vehicle to a complete stop.
2. Shift the transmission into N (Neutral).
3. Apply the parking brake and make sure it is holding properly.
4. Turn the engine off when you leave the vehicle.Never leave the
vehicle unattended when the engine is running.
Transmission fluid operating temperatures - 2200/2500 models
Allison 2200 and 2500 models:The sump/fluid reservoir temperatures
should not exceed 250°F (120°C). The converter temperature should not
exceed 300°F (144°C). he sump/fluid reservoir temperature should not
exceed 250 F (120 C).
TorqShift6-Speed models:The sump/fluid reservoir temperatures
should not exceed 250°F (120°C).
Allison 3000 series
The Allison 3000 Series offers two shift modes: Performance and
Economy. Performance Mode gives the best all-around transmission
operation; Economy Mode provides operation at lower engine RPM while
maintaining adequate performance. The transmission defaults to
Performance Mode when you start the engine. Pressing MODE on the
shifter activates Economy Mode and illuminates the Mode ON lamp.
If the engine speed is above idle when a gear is selected using the
shifter, the vehicle won’t move; the shifter must be moved to re-select a
gear after the engine speed returns to idle.
Note:For more information regarding the Allison 3000 Series, refer to
the separateAllison 3000 Series Operator’s Manual.
Torque lock
If your vehicle is parked on an incline and P (Park) is not properly
engaged (the parking brake is not applied before the transmission is
shifted into P [Park]), the weight of the vehicle may generate an
excessive amount of torque on the parking pawl, making it difficult to
shift the transmission out of P (Park). Hold the brake pedal down while
shifting out of P (Park), then release the parking brake.
Driving
135
2012 F-650/750(f67)
Supplement, 2nd Printing
USA(fus)

REAR AXLE INFORMATION
Axle operating temperature normally don’t exceed 100°F (38°C). If the
operating temperature exceeds 230°F (110°C), the rate of axle
lubrication oxidation increases and shorten the life of the lubricant and
seals, requiring axle lubrication changes to become more frequent to
preserve the axle. Extreme Pressure (EP) lubricants should not be run
consistently above 230°F (110°C).
Gross axle weight
Your truck has gross axle weight, gross vehicle weight and gross
combination weight ratings. Do not exceed these ratings.
WARNING:Exceeding these ratings by overloading can cause
component failure resulting in property damage, personal injury
or death.
Rear axles with locking or limited-slip differentials (if equipped)
If your vehicle is equipped with a locking or limited-slip differential, note
the following:
•Power is transmitted to the opposite wheel should one of the wheels
begin to slip.
•Both wheels must be raised off the ground should it be necessary to
operate one wheel with the vehicle stationary.
WARNING:If both wheels are not raised off the ground, the
one wheel that is not raised may pull the vehicle off its support,
possibly resulting in personal injury
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.
WARNING: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.
Driving
142
2012 F-650/750(f67)
Supplement, 2nd Printing
USA(fus)

Care should be taken to avoid sudden accelerations when both drive
wheels are on a slippery surface.
WARNING: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 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
provides full power to both axles.
When the differential is locked, the vehicle’s turning radius increases
(vehicle “under-steers”).
The differential can be locked or unlocked when the vehicle is moving at
a constant speed of under 25 mph (40 km/h) and while the wheels 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).
The differential lock and differential lock light automatically disengage at
speeds above 25 mph (40 km/h). The differential lock remains off until
either the vehicle is restarted or the differential lock switch is turned off
then back on.
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).
WARNING: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.
Driving
143
2012 F-650/750(f67)
Supplement, 2nd Printing
USA(fus)