2008 FORD SUPER DUTY light

LIMITED SLIP FRONT DIFFERENTIAL/LOCKING REAR
DIFFERENTIAL (IF EQUIPPED)
General information
Your vehicle may be equipped with a limited slip front differential and a
locking rear differential; vehicles equipped with these differentials should
be identified on the Safety Certification Label on the B-pillar or the edge
of the driver’s door. Vehicle handling characteristics will be different than
a conventional differential. Examples of this would be:
•When turning a corner, the sound of component disengagement and
re-engagement may be audible, and the transfer of driving torque from
both wheels to one wheel may be noticeable.
•When going from drive (acceleration) to coast (deceleration) in a
turn, a “metallic” sound may be heard as torque flow is reversed
(inside wheel engaged during acceleration; outside wheel engaged
during deceleration).
•When negotiating a turn (outside wheel disengaged), the inside wheel
under conditions of poor traction may receive excessive torque, which
could cause it to break traction momentarily until its speed is equal to
the outside wheel. This will result in re-engagement of the outside
wheel thus allowing both wheels to be driven. This condition is most
noticeable with lightly loaded axles.
Use extreme caution when accelerating or decelerating on
slippery or unstable surfaces. Vehicles/axles equipped with
traction differentials are inherently more sensitive to side-slip than
vehicles equipped with conventional differentials. Stability can be
retained if side-slip occurs by decelerating (letting off the accelerator).
Do not apply the brake. To do so may result in loss of vehicle control.
The vehicle’s braking capacity is reduced when a turn is made while
coasting downhill because the inside wheel is then disconnected from the
driveline. Operating in low gear will allow the engine to act as a retarder
and will improve braking capacity.
2008 F-250/350/450/550(f23)
Supplement
USA(fus)
Driving
20

Inspection and lubrication
When servicing any driveline components on a vehicle equipped
with a locking rear differential, ensure that the engine is off and
all wheels are off the ground to prevent the vehicle from moving. Axles
equipped with a locking rear differential deliver power to both wheels,
even when only one wheel is on the ground. Failure to observe these
cautionary measures may cause the vehicle to move which can result
in property damage, personal injury, even death.
This differential is designed to operate in the lubricant recommended by
the vehicle/axle manufacturer; no special lubricant is needed. Refer to
theMaintenance Product Specifications and Capacitiesin your
Owner’s Guidefor the proper axle lubricant. For very cold weather
applications, use the lightest oil the axle manufacturer will allow to
overcome possible sluggish re-engagement of the driven clutch
assemblies.
No adjustments or alterations should be made to the differential. Refer to
the vehicle/axle manufacturer’s instructions for adjustments to other
components in the axle.
SAND INGESTION
When driving through sand, traction or brake capability may be limited.
Also, sand may enter your engine’s air intake and severely damage your
engine or your vehicle may stall. Driving through sand where the
transmission vent tube or external breather kit is submerged may allow
sand into the transmission and cause internal transmission damage.
2008 F-250/350/450/550(f23)
Supplement
USA(fus)
Driving
21

The air coupling, to which the hose
is to be connected, is located on the
floor in front of the rear seat on the
passenger side.
The compressor is controlled by an
instrument panel mounted switch
below the radio. The compressor
cannot be turned on unless the
vehicle ignition is in the ON position
Note:The air compressor uses significant electrical current when
operating. It is recommended that the engine be running when the
compressor is in use to avoid discharging the battery.
When the compressor is switched to the on position, a light in the switch
will be illuminated and the reservoir pressure will increase until it
reaches the pre-set limit. The light will remain on even when the pre-set
pressure limit is reached and the compressor turns off. With the switch
turned on, the compressor may start at any time the ignition switch is in
the ON position. You should turn the compressor switch off until you
plan on using compressed air to avoid possible injuries and minimize
wear on the compressor and system.
Note:When the system is pressurized, all air lines from the compressor
to the outlet chuck are pressurized as well. Do not attempt to work on
the system or loosen any fittings unless you have drained all pressure
from the system by opening the drain on the air reservoir.
Whenever the air compressor has been used, be sure to drain the air
system of all pressure by opening the drain valve at the front of the
reservoir until air no longer escapes.Do not leave the system
pressurized when the vehicle is not in use.This will help to assure
the safety of those who may need to work on the truck and prevent the
condensation of water in the reservoir, extending the life of air system
components.
The air compressor inlet is equipped with a filter to prevent the
ingestion of contamination into the compressor and air system. This filter
is located underneath the truck, by the forward stake pocket on the left
2008 F-250/350/450/550(f23)
Supplement
USA(fus)
Tires, Wheels and Loading
23