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.
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.
Turn the engine off and raise all drive wheels of the locker differential
axle in order to prevent the vehicle from moving when servicing the
wheels, tires or brakes. Axles equipped with a NoSPIN Detroit Locker
differential 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.
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.
Fluid Temperature
Axle operating temperatures normally do not exceed 100°F (38°C).
If the operating temperature exceeds 230°F (110°C), the rate of axle
lubrication oxidation increases and shortens 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).
Axle Conversions
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.
144Transmission
2013 F-650/750(f67)
Owners Guide gf, 2nd Printing, March 2013
USA(fus)
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).
TWO-SPEED REAR AXLE (IF EQUIPPED)
WARNING:Never shift a two-speed axle when descending a
steep grade as this may cause loss of vehicle control and result in
personal injury.
Note:Do not shift between ranges when the speed control is on.
A two-speed rear axle allows the
driver to select a low range for
greater pulling power and a high
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 or fuel
economy may be factors.
Axle Shifting with a Manual Transmission
To downshift, select the next lower gear, release and press 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.
Axle Shifting with an Automatic Transmission
Note:You cannot split-shift with an automatic transmission. Also,
downshifting above 40 mph (64 km/h) may result in transmission or axle
damage.
Note:Do not shift the axle to LOW with the vehicle in motion.
Use LOW when you drive a fully-loaded vehicle on a severe grade or in
congested traffic. Press the upper portion of the switch.
Use HIGH for all normal driving conditions with a lightly-loaded or
partially-loaded vehicle. Press the lower portion of the switch.
2SPD
LOW
HIGH
Transmission145
2013 F-650/750(f67)
Owners Guide gf, 2nd Printing, March 2013
USA(fus)
HINTS ON DRIVING WITH ANTI-LOCK BRAKES
When the system is operating, the brake pedal pulses and may travel
further. Maintain pressure on the brake pedal. You may also hear a noise
from the system. This is normal.
The ABS does not eliminate the dangers inherent when:
•You drive too closely to the vehicle in front of you.
•Your vehicle is hydroplaning.
•You take corners too fast.
•The road surface is poor.
EXHAUST BRAKE (IF EQUIPPED)
WARNING:The exhaust brake is not recommended for use on
slippery or low traction road surfaces. Under these conditions a
loss of vehicle control could occur.
Note:Installing an exhaust or auxiliary brake does not necessarily
protect the engine from exceeding maximum governed speed. The
primary brakes should be used to make sure the engine never exceeds
maximum governed speed under any conditions.
Note:Before starting the engine, make sure that the exhaust brake
switch is pushed down to the off position. Do not turn the exhaust brake
on until the engine has reached normal operating temperature.
Note:Maximum exhaust brake performance is related to the type of
transmission your vehicle is equipped with.
Note:Engine speed has a major influence of retarding performance.
When engine speed is maintained at the maximum allowable level, the
exhaust brake operates at peak performance.
Note:Manual transmissions should be downshifted to the lowest gear
possible, without exceeding the maximum RPM limit of the engine.
This maximizes the exhaust brake’s retarding effect.
Note:Exhaust brakes operate effectively with automatic transmissions,
but performance varies with engine speed and the gear selected by the
transmission.
Brakes151
2013 F-650/750(f67)
Owners Guide gf, 2nd Printing, March 2013
USA(fus)
PARKING BRAKE
Hydraulic Brakes
WARNING:Do not use the gearshift selector in place of the
parking brake. Always set the parking brake fully AND make sure
the gearshift selector is in positionRfor vehicles equipped with a
manual transmission or positionP (if equipped)orNfor vehicles
equipped with an automatic transmission. Use of wheel chocks is also
recommended in hilly or off-road usage. Unexpected and possible
sudden vehicle movement may occur if these precautions are not taken.
WARNING:If the parking brake is fully released but the parking
brake warning lamp remains illuminated, the brakes may not be
working properly. See your dealer or a qualified service technician.
Apply the parking brake whenever the vehicle is parked. To set the
parking brake, pull the handle up until it snaps into the locked position.
When the parking brake is out of adjustment, seek service immediately.
The parking brake warning lamp in the instrument cluster
illuminates, and remains illuminated (when the ignition is
turned on), until the parking brake is released.
Push the palm release lever (A) on
the parking brake handle (B) and
push down as far as possible to
release the brake. Driving with the
parking brake on causes the brakes
to wear out quickly and reduces
fuel economy.
The parking brake is not recommended to stop a moving vehicle.
However, if the normal brakes fail, the parking brake can be used to stop
your vehicle in an emergency. Since the parking brake only applies
retardation to the rear wheels, the vehicle’s stopping distance increases
greatly and the handling of your vehicle is adversely affected.
Power Park (Hydraulic Brake Vehicles Only)
This feature uses a brake chamber mounted on the chassis to power a
spring-applied, hydraulically-released driveline parking brake.
P
A
B
158Brakes
2013 F-650/750(f67)
Owners Guide gf, 2nd Printing, March 2013
USA(fus)
Loosen the jam nut (A) and un-thread the adjustment rod (B) from the
chamber to reduce tension on the cable (C). Continue to un-thread the
adjustment rod all the way and remove it from the chamber. The nut and
shaft are metric.
Air Brakes
WARNING:Do not use the gearshift selector in place of the
parking brake; unexpected and possible sudden vehicle
movement may occur if these precautions are not taken. Always set the
parking brake fully AND make sure the gearshift selector is in position
Rfor vehicles equipped with manual transmission or positionN(except
Allison 2200 transmission) orP(Allison 2200 transmission) for vehicles
with automatic transmission.
If the service brakes should fail to operate while the vehicle is in motion,
you can make an emergency stop with the parking brake. Since the
parking brake only applies stopping power to the rear wheels, the
vehicle’s stopping distance greatly increases and the handling of the
vehicle is adversely affected. Repairs should be made immediately to an
inoperative air brake system circuit.
WARNING:This control is used for parking only. Do not leave
the vehicle unattended after setting the parking brake without
placing the transmission inpositionRfor vehicles equipped with manual
transmission or positionN(except Allison 2200 transmission) orP
(Allison 2200 transmission) for vehicles with automatic transmission.
Use of wheel chocks is also recommended in hilly or off-road usage.
CA
B
Brakes161
2013 F-650/750(f67)
Owners Guide gf, 2nd Printing, March 2013
USA(fus)
*Specific GCWR and maximum trailer weight applicable to a given
F–650/750 model is dependent on many variables including transmission
capability. Check with your sales consultant for the exact rating on your
vehicle.
ESSENTIAL TOWING CHECKS
Service your vehicle more frequently if you tow a trailer. See your
scheduled maintenance information.
For load specification terms found on the Tire Label and Safety
Compliance Certification Label and for instructions on calculating your
vehicle’s load, seeLoad limitin theLoad Carryingchapter.
Hitches
Do not use a hitch that either clamps onto the bumper or attaches to the
axle.
Distribute the trailer load so 10-15% of the total trailer weight is on the
tongue.
Safety Chains
Note:Do not attach safety chains to the bumper.
Always connect the trailer’s safety chains to the frame or hook retainers
of your vehicle hitch.
To connect the trailer’s safety chains, cross the chains under the trailer
tongue and allow enough slack for turning tight corners. Do not allow the
chains to drag on the ground.
Trailer Brakes
WARNING: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 crash greatly
increase.
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.
The braking system of the tow vehicle is rated for operation at
the GVWR not GCWR.
176Towing
2013 F-650/750(f67)
Owners Guide gf, 2nd Printing, March 2013
USA(fus)
Trailer Lamps
WARNING:Never connect any trailer lamp wiring to the
vehicle’s tail lamp wiring; this may damage the electrical system
resulting in a fire. Contact an authorized dealer as soon as possible for
assistance in proper trailer tow wiring installation. Additional electrical
equipment may be required.
Trailer lamps are required on most towed vehicles. Make sure all running
lights, brake lights, turn signals and hazard lights are working.
Before Towing a Trailer
Practice turning, stopping and backing up to get the feel of your
vehicle-trailer combination before starting on a trip. When turning, make
wider turns so the trailer wheels clear curbs and other obstacles.
When Towing a Trailer
•Check your hitch, electrical connections and trailer wheel lug nuts
thoroughly after you have traveled 50 miles (80 kilometers).
•Place the gearshift lever in positionP(if equipped) or neutral to aid
in engine and transmission cooling and A/C efficiency during hot
weather while stopped in traffic.
•Turn off the speed control. The speed control may turn off
automatically when you are towing on long, steep grades.
•Shift to a lower gear when driving down a long or steep hill. Do not
apply the brakes continuously, as they may overheat and become less
effective.
•Allow more distance for stopping with a trailer attached. Anticipate
stops and brake gradually.
FIFTH-WHEEL OPERATION
WARNING:Failure to follow the fifth-wheel manufacturer’s
instructions for hooking and unhooking as well as sliding the
fifth-wheel could result in an accident, personal injury or death.
WARNING:When the tractor and trailer are parked unattended,
the trailer brake hand control should never be used to apply the
brake, since air may leak from the system, allowing vehicle movement,
resulting in possible property damage, personal injury or death.
Towing177
2013 F-650/750(f67)
Owners Guide gf, 2nd Printing, March 2013
USA(fus)
Do not attempt to push-start your automatic transmission vehicle.
Automatic transmissions do not have push-start capability. Attempting to
push-start a vehicle with an automatic transmission may cause
transmission damage.
Six-speed TorqShift® transmissions have an adaptive shift strategy.
When the battery is disconnected or a new battery is installed, the
automatic transmission must relearn its shift strategy. As a result, the
transmission may have firm soft shifts, firm shifts or both. This operation
is considered normal and does not affect function or durability of the
transmission. Over time, the adaptive learning process fully updates
transmission operation.
Preparing Your Vehicle
Note:Use only a 12–volt supply to start your vehicle.
Note:Do not disconnect the battery of the disabled vehicle as this could
damage the vehicle’s electrical system.
1. Park the booster vehicle close to the hood of the disabled vehicle
making sure the two vehicles do not touch. Set the parking brake on
both vehicles and stay clear of the engine cooling fan and other
moving parts.
2. Check all battery terminals and remove any excessive corrosion
before you attach the battery cables. Make sure that vent caps are
tight and level.
3. Turn the heater fan on in both vehicles to protect from any electrical
surges. Turn all other accessories off.
Connecting the Jumper Cables
WARNING:Do not connect the end of the second cable to the
negative (-) terminal of the battery to be jumped. A spark may
cause an explosion of the gases that surround the battery.
Note:Do not attach the negative (-) cable to fuel lines, engine rocker
covers, the intake manifold or electrical components as grounding points.
Note:In the illustration, the vehicle on the bottom is used to designate
the assisting (boosting) battery.
186Roadside Emergencies
2013 F-650/750(f67)
Owners Guide gf, 2nd Printing, March 2013
USA(fus)