2013 FORD F750 differential lubrication

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)

Climate Control System
Have the air conditioning system checked each spring. The refrigerant
charge, cleanliness of the condenser-evaporator cores and belt condition
are essential to system performance.
When the air conditioning system is being used daily, remove the fresh
air filter (if equipped) once each season and check for dirt, lint, etc.
Replace the filter if necessary. Vehicles operating in unusually dusty
conditions may require more frequent filter inspection and replacement.
Front Axle
Maintaining the front axle alignment to specifications is very important
and should only be performed by a qualified technician. Regular
inspections should include:
•toe-in inspection and adjustment (if necessary), particularly with
radial tires.
•checking for proper tightness of axle mounting U-bolt nuts, attaching
or mounting bolts and nuts.
•checking the axle for damage, binding, worn parts and adequate
lubrication..
•checking the kingpins for excessive wear. This should also be done
during other scheduled maintenance (tire rotation or service, wheel
bearing service, alignment, etc.). See the workshop manual for proper
procedures.
Toe-in
It is essential that correct toe-in and tire pressure be maintained for
optimum tire wear.
Inspecting steer axle tires in the first 3000–10000 service miles
(5000–16000 service kilometers) generally shows 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, 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 equals
12steer axle loading).
206Maintenance
2013 F-650/750(f67)
Owners Guide gf, 2nd Printing, March 2013
USA(fus)

Special applications may warrant a setting based on 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 does not drastically improve tire tread life.
Rear Axle
Regular inspections should include:
•checking for proper tightness of axle mounting U-bolt nuts, attaching
or mounting bolts and nuts. SeeSpring U-bolt checkslater in this
chapter.
•checking the axle for damage, binding, worn parts and adequate
lubrication.
NoSpin Detroit Locker Positive Locking Differential
Vehicles equipped with this type differential have the operator’s manual
supplied with the vehicle. See that manual for maintenance inspections.
Maintenance207
2013 F-650/750(f67)
Owners Guide gf, 2nd Printing, March 2013
USA(fus)