Ford F-650 Owner's Manual page 142

Driving
REAR AXLE INFORMATION
Axle operating temperature normally don't exceed 100°F (38°C). If the
operating temperature exceeds 230°F (110°C), the rate of axle
lubrication oxidation increases and shorten 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).
Gross axle weight
Your truck has gross axle weight, gross vehicle weight and gross
combination weight ratings. Do not exceed these ratings.
WARNING: Exceeding these ratings by overloading can cause
component failure resulting in property damage, personal injury
or death.
Rear axles with locking or limited-slip differentials (if equipped)
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.
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
Driver-controlled differential lock
To prevent the vehicle from moving when servicing the wheels, tires or
brakes, turn the engine off and raise all drive wheels of the locker
differential axle. Axles equipped with NoSPIN Detroit Locker differentials
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.
142
2012 F-650/750 (f67)
Supplement, 2nd Printing
USA (fus)