Dodge 2005 DH Ram Owner's Manual page 240

240 STARTING AND OPERATING
When To Use "TOW/HAUL" Mode
When driving in hilly areas, towing a trailer, carrying a
heavy load, etc., and frequent transmission shifting oc-
curs, press the "TOW/HAUL" button. This will improve
performance and reduce the potential for transmission
overheating or failure due to excessive shifting. When
operating in "TOW/HAUL" mode, 5th gear (if
equipped) is disabled and 2-3 and 3-4 shift patterns are
modified. Shifts into Overdrive (4th gear) are allowed
during steady cruise (for improved fuel economy) and
automatic closed-throttle downshifts to 3rd gear (for
improved braking) will occur during steady braking.
The "TOW/HAUL" light will illuminate in the instru-
ment cluster to indicate when the switch has been
activated. Pressing the switch a second time restores
normal operation. If the "TOW/HAUL" mode is desired,
the button must be pressed each time the engine is
started.
When To Lock Out Overdrive
When driving in hilly areas, towing a trailer, carrying a
heavy load, etc., and frequent 4–3–4 transmission shifting
occurs, press the "TOW/HAUL" button. This will im-
prove performance and reduce the potential for transmis-
sion overheating or failure due to excessive shifting.