Ford F-150 2010 Owner's Manual page 304

Driving
Using the electronic shift 4WD system (if equipped)
2H (4X2) - Power to the rear
wheels only; used for street and
highway driving. Provides optimal
smoothness and fuel economy at
high speeds.
4H (4X4 High) - Used for extra
traction such as in snow or icy roads
or in off-road situations. Not
intended for use on dry pavement.
4L (4X4 Low) - Uses extra gearing
to provide maximum power to all
four wheels at reduced speeds. Intended only for off-road applications
such as deep sand, steep grades or pulling heavy objects. 4L (4X4 Low)
will not engage while the vehicle is moving above 3 mph (5 km/h); this is
normal and should be no reason for concern. Refer to Shifting to/from
4L (4X4 Low) for proper operation.
Shifting between 2H (4X2) and 4H (4X4 High)
Move the 4WD control between 2H (4X2) and 4H (4X4 High) at any
forward speed. The message center will display 4X4 SHIFT IN
PROGRESS during the system shift. "4X4 HIGH" will display in the
message center if 4H is selected and "4X2" will momentarily display in
the message center if 2H is selected.
Note: Momentarily releasing the accelerator pedal while preforming a
shift will improve engagement/disengagement times.
Note: Do not perform this operation if the rear wheels are slipping.
Note: Some noise may be heard as the system shifts or engages; this is
normal.
Note: 4X4 High mode is not intended for use on dry pavement.
Shifting to/from 4L (4X4 low)
1. Bring the vehicle to a speed of 3 mph (5 km/h) or less.
2. Place the transmission in N (Neutral).
3. Move the 4WD control to the desired position.
The message center will display 4X4 SHIFT IN PROGRESS during the
shift. The message center will then display the system mode selected. If
any of the above shift conditions are not met, the shift will not occur and
the message center will display information guiding the driver through
the proper shifting procedures.
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