Ford 2013 F-650 Owner's Manual page 144

To engage the PTO unit, stop the vehicle and place the transmission in
position N. Press the clutch and allow the gears to stop rotating, then
engage the PTO unit. The PTO can also be selected with the
transmission in gear as long as the clutch is pressed.
When operating the PTO with the vehicle stationary, first set the parking
brake (chock the wheels if the vehicle is on a hill or another uneven
surface).
REAR AXLES
Gross Axle Weight
WARNING: Exceeding these ratings by overloading can cause
component failure resulting in property damage, personal injury
or death.
Your truck has gross axle weight, gross vehicle weight and gross
combination weight ratings. Do not exceed these ratings.
Locking or Limited-Slip Differentials
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
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.
Driver-controlled Differential Lock
Note: Never use the differential lock at vehicle speeds above 25 mph
(40 km/h).
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
(under-steer).
2013 F-650/750 (f67)
Owners Guide gf, 2nd Printing, March 2013
USA (fus)
Transmission 143