FORD 2013 F-550 v.1 - Manual (Page 199)

D (Overdrive) with Tow/Haul On
The tow/haul feature improves transmission operation when towing a
trailer or a heavy load. All transmission gear ranges are available when
using tow/haul.
To activate tow/haul, press the
button on the end of the gearshift
lever.
The TOW HAUL indicator light will illuminate in the instrument
cluster.
Tow/haul delays upshifts to reduce frequency of transmission shifting.
Tow/haul also provides engine braking in all forward gears when the
transmission is in the D (Overdrive) position; this engine braking will
slow the vehicle and assist the driver in controlling the vehicle when
descending a grade. Depending on driving conditions and load
conditions, the transmission may downshift, slow the vehicle and control
the vehicle speed when descending a hill, without the pedals being
pressed. The amount of downshift braking provided will vary based upon
the amount the pedal is depressed.
To deactivate the tow/haul feature and return to normal driving mode,
press the button on the end of the gearshift lever. The TOW HAUL light
will no longer be illuminated.
When you shut-off and restart the engine, the transmission will
automatically return to normal D (Overdrive) mode (Tow/Haul OFF).
3 (Third)
Transmission starts and operates in third gear only.
Used for improved traction on slippery roads. Selecting 3 (Third)
provides engine braking.
2 (Second)
Use 2 (Second) to start-up on slippery roads or to provide additional
engine braking on downgrades.
TOW/HAUL
198 Transmission
2013 F-250/350/450/550 (f23)
Owners Guide gf, 1st Printing
USA (fus)