[Jackpine]

Shotgun and F150 Man, here's what Bill has said about towing:

Anything below about 2000# is probably all right in any tune. More than that and you DO want to use a "towing" tune. It has a slightly richer mixture, which helps to keep things cooler and the shift points are set to minimize strain on the transmission.

I generally leave my O/D ON as long as the transmission is not constantly shifting between 3 & 4 or the Torque Converter is not constantly unlocking and locking back up. Basically, you want to keep the "activity" in the transmission at a minimum. I'll also lock out the O/D when descending long hills to use engine braking.

If the hills are really steep (up or down) I put the transmission in 2nd.

If your boat is 4000#, DO use the tow tune. Let the transmission tell you what to do about O/D (there's no point in wasting gas if the load is low in a level cruise).

I monitor CHT, TFT, Comm Gear, and Batt Voltage when I tow. Seeing the status of the TC and transmission gear that's commanded helps me decide on which gear to use and the battery voltage is because I'm charging two trailer batteries and a DC refrigerator in addition to the truck's battery. I was able to tell that I'd blown the trailer battery charging fuse this way.

For what it's worth, I actually think the tow tune is a pretty good "all around" tune.

And, Shotgun was correct in directing you to the Towing forum. There's some good information in there. Have a good trip!

- Jack