How important is 3.73 axle for large trailers?

[JasonH]

The 3.73’s also help in tow haul mode to engine brake in deceleration. They aren’t just more torque/power.

Good point, I haven't done any driven any major hills yet so have not relied on the tranny to control speed on a decline. Are any of the other gear ratios altered when a shorter final drive is used? The vehicles all get the same MPG rating...but all things being equal shouldn't the shorter final gear lower mpg?

When TFL Truck tested the Expedition towing they said it required several brake applications to control downhill speed. Why not just downshift to reduce the need for manual brake application?

 

[Langer]

I was going off the Ford towing guide. Looks like both the 3.31 and 3.73 can tow 9200# if they have the tow package. I have seen enough 3.31's with brake controllers to know that they have the HD tow. Was wondering if anyone has the 3.31 and comfortablely tows around 7000#. https://www.google.com/url?sa=t&sou...FjAAegQIARAB&usg=AOvVaw1l_FrLEgli0gjdBuCRXwP6

I have a 2017 XLT 4x4 with 3.31, and added trans cooler, brake controller, 7-pin, etc, and tow my 28’ boat with no issues. The boat is 6200# dry, trailer 1000#. With equipment and gas I’d imagine I’m close to max capacity. Positives exist for the better gearing, but definitely not problem for the truck.

 

[JasonH]

I've noticed during my current drive from Houston to FL that the transmission will downshift agrressively in tow/haul mode to help control speed. It was dropping into 1 - 3 gears on hills and bridges when going downhill.

 

[coolzzy]

At speeds above probably 20mpg, tow haul will only downshift you to 2nd gear on a slope, and the ecoboost does not have enough displacement to engine brake very well. 2nd gear will still roll downhill at 50mph with a trailer behind you at roughly 4k rpm and that's as far as I've let it push before using the brakes. It would roll faster still if you let it...

 

[johnboneske]

I have a 2017 XLT 4x4 with 3.31, and added trans cooler, brake controller, 7-pin, etc, and tow my 28’ boat with no issues. The boat is 6200# dry, trailer 1000#. With equipment and gas I’d imagine I’m close to max capacity. Positives exist for the better gearing, but definitely not problem for the truck.

don't forget there is a HUGE difference between pulling a boat and a camper. Boats are aerodynamic, campers are bricks... I used to pull our 26' Rinker with a minivan without any issues when going a short distance and it weighed around 6k. Pulling a 7k TT with my Expedition is a big difference.