Originally Posted by Neal H.
Can someone tell me the best way to use this option? Thank you.
Yes. When towing, engage Tow/Haul and leave it alone.
Unlike older Tundras with overdrive (like my 2005), the Tow/Haul "alerts" the transmissions computer to analyze its inputs using a different set of computations. This results in altering up- and downshifts. It also allows the tranny to go into its highest gear, even when towing. Also, you'll notice the tranny responds to braking by downshifting more quickly.
Set it and forget it. That transmission knows more about its job than we do.