Towing in overdrive?

i have a 08 v6 with the towing package. I am pulling a 17' boat weighing about 1500 pounds. Do I need to tow only in 4th out of overdrive? Rpm are about 2400 going 60. Is it ok to pull in overdrive on the flat areas and drop it out of overdrive on hills? Gas mileage dies in 4th but it's cheaper than buying a new tranny. And input would be great

 

Overdrive is fine

 

^^^ THIS

 

I pulled a 1800 lbs pop-up camper with at least another 300 lbs of gear in storage.
Plus another 250 lbs of stuff in the bed of the truck.

That's ~2300 lbs.

I pulled in OD on the interstate @ 70 mph.
The key is to keep it in one gear. If you find the Trans switching from gear to gear.
Drop to 4th.

Actually, my truck seems to stay in OD and pulled fine as long as I stayed above 2,000 rpm.
Once you tow enough you'll know what gear you need.

I do how ever always use 4th if I'm not on a highway. Or at speeds below 55 mph.

Yes, I've pulled a lot more weight than 2300 lbs. But this weight is the closest to your boat.