gregt909

I'm looking to purchase a 2013 screw FX4 with the Eco Boost engine. I don't tow very often but when I do it's a 7000lb boat. Usually only tow it 100 miles or so max. I'm thinking of getting the 3.55 gears for a little better mileage on the highway what do you guys think?

CPT150

arent 13 Eco equipped with 3.55 gears? Do you plan on doing any mods ot the truck...lift, tires? Take that into consideration as well, so you dont have to regear later...also, do they make gears specifically for 13's yet?

JaysonsF150

It's a personal preference, for me I how my buddies 5000# boat periodically for a few hours and I run 3.31 gears. No effort at all. I was looking at swapping 3.55's in just to have a little bit more for the hills. You'll be happy with either, honestly the benefit to fuel economy will be very minor

gregt909

the 3.73 gear is a $570 upgrade and many of the trucks I have looked at have them. Of course the dealer I can get the best deal with has the 3.73's. I plan to leave the truck with the stock height and tire size so no worries there.

CPT150

well, with 3.73s and stock, you should be getting some real good gas milage. Id go with the 3.73s if you are going to keep it stock/ if you want to bump your tire size up a little bit, your still good, and towing, your still in the green. honestly, sounds like a win/win to me by going to 3.73

gregt909

I thought the 3.73's would get worst mileage on the highway (spinning higher rpm's) Am I wrong?

caperJ

I just went through the same issue. Purchased a new 13 Eco and drove one with 3.31 and 3.73 I chose the 3.73. Gas mileage is the same as my 5.0 with 3.55. It all comes down to preference, if you buy 3.31 and don't like em you can upgrade the gears at a cost or you can just get the 3.73 from the get go. Like others have said the mileage difference is minimal. If you can take both out for a test ride and decide from there. Towing will be maxed at close to 8000 with 3.31 gears. I have the ma to package with 3.73 so I believe its 11,500. The bumper can only go up to 5000 so you will need a tow package either way.

Left Plate

If towing is your priority get the 3:73s. If mileage is your priority get the 3:55s.

engineermike

Looking at the chart, even the 3.31 gear is rated for over 9000 lb towing. I have 3.15's in mine and couldn't be happier with the mileage and performance. Keep in mind that the new 6r80 transmission has a super-low 1st gear, thereby making the rear gear ratio much less significant.

ultradriver10000

Go with the 3.73's, they are better for hairy burn outs.

You honestly won't notice a difference.