When should I use the tow/haul?

[kmitchl]

Use it when you are towing and having to go really slow. You don't have the engine speed and vehicle speed to get enough air flow across the transmission cooler to cool the fluid. The tow setting will keep the engine RPM's up to ensure adequate air flow. Ask me how I know this!

[DEADEYE1]

I think if you are worried about gas mileage you might should have not bought a hemi

[Mike D]

I think if you are worried about gas mileage you might should have not bought a hemi

I kinda agree with this. You are focusing on fuel mileage and tow/haul mode will only slightly affect your mileage is any at all. But it will save your transmission.

[Grumpy1911]

Clear as Mud now?!

[Javelin]

Tow haul does not keep it or of overdrive. On the 545re transmission on the dodge, it lengthens the shift points and holds gear much longer. It also makes for a much more firm shift by commanding more line pressure thus giving a harder faster shift. Lastly it holds gear under breaking to help engine breaking

This. On both dodge and ford not sure on Chevy but it still goes into all gears and overdrive but it moves shift points

If your truck pulls your load with not much shifting you really don't need to use it but if it is hunting for gears do so

[Tbar]

On a Ford.......only lock out overdrive if/when the transmission starts hunting/downshifting.