that was a great link. Looks like it is a bit more sophisticated than the old setup on GC. This from the site:
When To Use "Tow / Haul" Mode
When driving in hilly areas, towing a trailer, carrying a heavy load, etc., and frequent transmission shifting occurs, 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, the transmission will shift to 3rd gear and 4th will be enabled under steady cruise conditions.
Tow / Haul Button
The "Tow / Haul" light will illuminate in the instrument 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 switch must be pressed each time the engine is started.
Looks like it goes to 3rd gear automatically, but will auto shift to 4th if conditions permit.
Apepars to be better able to protect itself from overheating.
If it hunts gears on me, I can always use the slapstick and put it in 3rd manually.
Nice enhancement though.