FORD 2002 F-550 v.1 - Manual (Page 214)

To prevent the vehicle from
moving when you change a
tire, be sure the parking brake is
set, then block (in both
directions) the wheel that is
diagonally opposite (other side
and end of the vehicle) to the tire
being changed.
2. Turn engine OFF and block the diagonally opposite wheel (block not
provided).
3. Remove the jack, jack handle, lug wrench and spare tire from the
stowage locations.
4. Use the tip of the lug wrench to remove any wheel trim.
5. Loosen each wheel lug nut
one-half turn counterclockwise but
do not remove them until the wheel
is raised off the ground.
When one of the rear wheels is off the ground, the transmission
alone will not prevent the vehicle from moving or slipping off the
jack, even if the transmission is in P (Park) (automatic transmission)
or R (Reverse) (manual transmission). To prevent the vehicle from
moving when you change the tire, be sure that the parking brake is set
and the diagonally opposite wheel is blocked.
If the vehicle slips off the jack, you or someone else could be
seriously injured.
Roadside emergencies
214