I have an October 08 build date with no Fuel Save light. For those of you that have the fuel save light, does the MDS kick in when using 4WD Auto or 4WD Lock? I know that MDS is disabled in Tow/Haul mode, but I wasn't sure about 4WD.

 

It works in 4WD Lock. Was playing around with mine today in the snow and the MDS was definitely kicking in and out. I would think that 4WD Auto would be the same although I can't test that for you.

 

What does Tow/Haul actually do, i heard if you get stuck bad and need to really spin yours tires to keep moving you know those rare big huge snow storms or you turn the corner into a street that is pristine virgin foot of snow in a 2wd pickup..so should you use Tow/haul in that instance?

 

Tow/Haul disables MDS, activates an altered ESP setting that includes trailer sway control programming, and also engages a more aggressive transmission mode that downshifts quicker (to get the truck into the power band) and also downshifts when slowing down to utilize engine braking to help preserve the brakes.