Whats the ratio go to when on tow haul with the stock 3.92 gears? I noticed i get better mpg in town when I turn it on. Someone said 3.98 or something idk...My rpms shift higher helps alot

 

the ratio you are talking about is the rear end ratio. it's a ratio determined by the physical size and the numbe rof teeth on the gears in the differential. can't be changed by a button.

by putting it in tow/haul mode you are telling your transmission not to go into overdrive, and maybe it is programmed to lock the torque converter faster? It is a pretty good idea for city driving since it keeps you from going into gears that require more effort from the engine. it will also extend the life of your transmission by keeping it from making unnecessary shifts since you will likely be stopping and shifting back down soon.

 

+1 Couldn't have said it better myself!

 

Tow/haul still allows 4th...at least in my 07. I've noticed the the shifts points are higher and less throttle is required to kick down a gear...and when it does kick down it holds the gear for awhile even under light throttle.I'm not sure which year they added theo/d off feature to the button...i'm thinking 06? That button obviously shuts off o/d...maybe the two are combined in earlier years?

 

That's how my 08 works. tow/haul locks out 5th gear, raises the 2-3 and 3-4 shift points and will downshift automatically on a downgrade is it sees the speed increasing with no gas pedal input.
OD/off turns off 4th and 5th.