"Tow mode
Tow mode should be used when pulling a heavy
trailer or hauling a heavy load. Press the tow
button to activate the tow mode. The tow indicator
in the instrument panel illuminates when the
tow mode is selected. Press the Tow button
again to turn the tow mode OFF. The Tow mode is
automatically cancelled when the key is turned
OFF.
The Tow mode does the following:
1. Reduces transmissions shifts when pulling a
trailer or hauling a load.
2. Provides similar shift feel to driver when the
vehicle is towing.
The Tow mode should be used when the vehicle
and trailer weight is at least 75% of the vehicle's
GCWR. Tow mode is most useful in the following
driving conditions when towing a heavy trailer or
hauling a heavy load:
1. Rolling terrain.
2. Stop and go traffic.
3. Busy parking lots.
Driving the vehicle in the Tow mode with no
trailer/load or light trailer/light load will not cause
any damage. However, fuel economy may be
reduced and the transmission/engine driving
characteristics may feel unusual.
Taken from the manual. I never noticed but in my manual anyway there is a ton of towing information. Even how to wire the brake controller and a host of other information. Take a few minutes and have a read, it's really quite interesting!