Originally Posted by wolftree
Given your location, you will not be dealing with mountains, but serious heat. I would say yes to adding a transmission cooler. A good unit should give you no leaks anywhere. Most are saying now to come from the transmission, to the aux cooler then back to the radiator, finally returning to the transmission. This heats the fluid during winter months.
Yes, just place it "3" to hold it out of overdrive. You may find though that given your load, you can run in overdrive. Try it, as long as it is not constantly shifting up and down, run in it.
The only difference between standard and "towing package" is the hitch/harness, provisions for electric brakes, and the trans cooler.
Also +1 on the trans.
The 4-banger has only a 4-speed auto, so holding it in "3" will keep it out of overdrive, BUT, towing in overdrive is not a bad thing as long as the trans remains in one gear.
Heat is what kills your trans, and repeated clutch application during shifting generates heat. Some heat is produced in the torque convertor, but that is less of an issue on modern TC's that have a lockup clutch and effectively go into direct drive.
Try towing in "D". If the trans is not "hunting" for a gear (shifting back and forth between 3rd and OD), leave it in "D".
If it starts shifting back and forth, then pop it into "3".
The fuel savings will be significant, especially if you are not towing a heavy trailer.