FORD 2013 F-550 v.3 - Manual (Page 211)

Note: Auto-manual hub locks can be manually overridden by rotating the
hub lock control from AUTO to LOCK.
For proper operation, make sure
that each hub is fully engaged and
that both hub locks are set to the
same position (both set to LOCK
or both set to AUTO). To engage
LOCK, turn the hub locks
completely clockwise; to engage
AUTO, turn the hub locks
completely counterclockwise.
The ESOF 4WD system:
• provides 4x4 High engagement and disengagement while the vehicle is
moving.
• is operated by a rotary control located on the instrument panel that
allows you select 4x2, 4x4 High or 4x4 Low operation.
• uses auto-manual hub locks that can be engaged and disengaged
automatically based on the 4x4 mode selected.
• will increase fuel economy when used in the recommended AUTO lock
mode.
4WD Indicator Lights
The indicator lights illuminate in the message center in the
reconfigurable telltale (RTT) location under the following conditions.
Refer to Warning Lamps and Indicators in the Instrument Cluster
chapter.
Note: When a 4X4 system fault is present, the system will typically
remain in whichever 4X4 mode was selected prior to the fault condition
occurring. It will not default to 4X2 in all circumstances. When this
warning is displayed, have your vehicle serviced by an authorized dealer.
4X2 - Momentarily illuminates when 2H is selected.
4X4 HIGH - Continuously illuminates when 4H is selected.
210 Four-Wheel Drive (If Equipped)
2013 F-250/350/450/550 (f23)
Owners Guide gf, 3rd Printing, December 2012
USA (fus)