you want to make sure that you only use it going up hills .when i did my first haul i thought that you had to have the tow mode on all the time, so here i am going down the highway reving the crap out of my motor . noy a good first experience

 

In my 2004 Durango tow/haul locks out 5th but still allows 4th OD. When towing it usually stays in 3rd unless perfectly flat or downhill.

On my 2007 ram tow haul only changes shift points. It does not lock out any gears. Whats nice is that there is a manual lockout feature that allows me to tell it what the highest allowable gear is from 1st to 6th. Seems like Dodge finally found they cant make programming changes that work for everyone. Manual selection is something I've felt was badly needed years ago.