FORD 2011 F-550 v.4 - Manual (Page 281)

For 2WD vehicles and vehicles
equipped with a manual shift
4WD system:
Turn the control to ON. The
indicator light will display in the
instrument cluster.
Once the light is displayed in the instrument cluster, both rear wheel
axle shafts will be locked together providing added traction.
If the indicator light in the instrument cluster turns off, one of the
following has occurred:
• The vehicle speed is too high.
• The left and right rear wheel speed difference is too high during an
engagement attempt.
• The system has malfunctioned and will be accompanied by the
CHECK LOCKING DIFFERENTIAL message in the message center.
See your authorized Ford dealer for assistance.
Note: The ELD may have difficulty disengaging either by operator
command or automatically if the driveline is under torque. If driving
conditions allow, releasing the accelerator pedal or turning the steering
wheel in the opposite direction may assist in disengagement.
Note: The ELD is designed for off-road use only and is not intended for
use on dry pavement.
PREPARING TO DRIVE
WARNING: Utility vehicles have a significantly higher rollover
rate than other types of vehicles.
WARNING: In a rollover crash, an unbelted person is
significantly more likely to die than a person wearing a seat belt.
Utility vehicles and trucks have larger tires and increased ground
clearance, giving the vehicle a higher center of gravity than a passenger
car.
Driving
281
2011 F-250/350/450/550 (f23)
Owners Guide, 4th Printing
USA (fus)