[duramaxin14]

Originally Posted by ob_1jr

Tow/haul mode never locked out overdrive (that I'm aware of)...on the 03 and newer they had a new feature that you could lockout overdrive if your truck was hunting for a gear. As far as T/H I use it when I am going to be doing a lot of stop and go and also up and down hills. T/H locks your torque converter in second gear and up. I'm not real sure the difference with the 6 speed, but I am pretty sure it is the same.

x2 I run tow haul when sled pulling drag racing and pulling very heavy loads. No i do not have to but allison trannys have 2 differnt ways of learning Your driveing habbits ( In 03 and up) U have normal driving habbits which is like the way u drive around town and stuff then when u push tow haul its use to what u usally give it. Thats the nice thing about it