Ford F-250 7.3 Gas Engine Axle Ratios

Been pulling trailers 45 plus years, starting with pop-ups. Most of our travel trailer towing these days is about 600 miles one way to 8K ft. mountains, the Texas coast, and to Nashville, Tennessee.

Our trailer weighs 6000lbs wet and loaded, with about 400 lbs. of generator and gear in bed of the truck. Currently we have an old bullet proof 7.3 2002 diesel which wife and I have owned and enjoyed tremendously for 17 years. We average 13 mpg towing. But like me, our wonderful truck is getting old with 255,000 miles on it.

Do not want to plan long trips going from gas stations to gas stations, as a couple we travel/camp with must do with their 2012 Chevy 3/4 ton gasser towing about 7000 lbs. trailer.

We are Ford folks..Blue Oval all the way. Could afford a new 6.7 diesel, but there are a lot of new hidden maintenance costs that go along with all new 2020 diesels.

Just thinking our next truck might be the new Ford F-250 with the 7.3 gas engine. But the reported terrible MPG towing gives me a lot of pause.

Real world towing and around town mileage from 7.3 gas owners would be appreciated. Perhaps there has been improvement in the 2021 models?

TECMike wrote:
Is there much difference in towing milage, and around town/highway mileage with the new F-250 7.3 gas engine with rear gear options?

Considering 3.55 or 4.30 axles ratios. Any input is helpful.

The only transmission available is the new 10R140.

The 4.30 would be great for pulling stumps or towing over 10,000 lbs, but the fuel economy would not be very good. It depends if they can program the transmission to start in 3rd or even 4th with a light load (driver only).

Personally, I would go with the 3.73 and electronic locking differential.

As with any gasser, the deeper gears are always the best way to go. And with the 10speed the mileage loss will be small if any loss at all.

What transmission?

What usage...daily driver and occasion tow
OR tow only?

Do you need a 4.30 rear axle with 7.3 liter engine? Texas is far from the Rockies, Sierra and Appalachians.