I've used the tow/haul mode for a while now, it was just really an experiment to see what exactly it did and how it effects mileage and so on. I now use it all the time, towing or not...I have a topper on the bed and some firewood that I keep in there so when we go camping, i don't have to pack and unpack. So the load i have right now is near nothing, but over time, i've noticed that the shifting has really become smoother, not that harsh engage/disengage like everyone is noticing. As for mileage, I actually see an increase in mileage when i'm driving around town in the 40/45mph zones...nothing different on the highways tho(75). When i tow my camper or the dump trailer, i notice that the shifting pattern allows me get going a bit quicker then having it in non-t/h mode, without as much effort and that could be important, depending on the traffic around you. As others have said, use it...you'll notice a difference and probably for the better.