Originally Posted by keith_h
I only use it in the mountains. Mainly for the transmission/engine braking going downhill. Every place else I just use regular mode. It also looked to me that my mileage is a bit better, 1 or 2 mpg, by not using it for driving on your typical flat to somewhat hilly highways.
X2 on this and many other similar answers.
YOU should experiment with you own driving style. From my experience for example driving down the interstate highway say at the same speed as some semi trucks then you come to a moderate down hill grade. When NOT in tow mode there will be a increase in coasting speed the same as the semi does. When you start up a moderate grade say in cruise control it will maintain speed fine. At this time the semi may fall back more in speed than you.
IF IN TOW MODE the braking action that the transmission goes into will slow you down and maintain cruise control set speed or if not in cruise will slow down below your flat land speed if you let off the gas. Going up grade the shift points are changed dropping into lower gears to climb the grade.
RESULT is the semi will pass you down hill then you may catch up going up hill and possibly pass him.
I find driving similar to the traffic that may be going my speed is easier than jockeying positions all the time.
LARGE HILLS is another story use TOW MODE or manual shift if that works better.
Whatever you find works best for you is the way to go.
Enjoy your new toy and GET OUTDOORS.