AKFX4

I have a 2013 FX4 w/3.73, running 275/70 18's 2" lvl and get between 14.7 and the best I have got is 16.1 for about two milliseconds and got bored driving 55, love it.

Adobe2X

For heaven's sake, just GET the 3.73's and be done with it. They are great gears for the EB because they keep the engine right in the sweet spot at the beginning of the torque curve on the highway -- just shy of 2,000 rpm.
With these gears at highway speed, you will love how the EB never, and I mean NEVER downshifts at freeway speeds, regardless of the grade!

eteele

My mom has a 2012 EB fx4 lariat crew cab and when she comes from missouri to visit me in louisiana she averages aroumd 23-25 mpg and she drives 70-75! I dont know why yall are getting such horrible fuel mileage!!

jerparker1

FX4 Lariat? Never heard of such a thing. Did you create an account just to stir up sh*t?

Driver72

I'm not "worried" per se, just that I drove the 3.55 and liked it.
I also had the 3.55 in my Mustang 5.0 and to me it's the best combo of
performance when needed and economy when cruising.
I'd like a truck for the occasional trips to the Lowe's as well as picking up supplies and also the occasional light duty off road excursions. Then there is the times when we get lots of rain and the roads can get a foot of water that I'm always not willing to drive in with my car.

But the reality is, 90% of the time, I won't need a truck, so in those cases, while commuting, it would be nice to get gas mileage in the upper teens per gallon. Just wasn't sure if the 15 city / 21 hwy (17 combined) figure the EPA has on the truck is anywhere close to what you get with the 3.73 gears.
I'd easily expect that with the 3.31's and even possibly with the 3.55's if driven softly, but I was skeptical with the 3.73's.
It seems doubtful you could get 21 mpg on the highway with the 3.73's considering that you are running probably 400 rpms higher at 70 mph than you would with a 3.31 axle.

Thanks to those who chimed in about their real world MPG's with their eco 4x4 with 3.73's

Driver72

I think he meant 4x4 lariat

captainnemojr

iTrader: (1)

I have a truck exactly like you are looking at. I get 17.5 on the hwy going 75-80. At those speeds, the RPM is about 2050. I got 16 on a hunting trip with 4 people (avg weight 250 per person) and a bed full of gear.

Just remember those EPA figures are for a short bed, regular cab, 4x2 EB with the 3.31 rear end.

Brutus10

Can't speak for 2012 but on the 2013s the lariat offroad package comes with 3.55.

packplantpath

Probably the 3.15 rear end.

94-F150-10

3.31 vs 3.73 would be a little over 200 rpm difference at 70 mph but 3.55 vs 3.73 would be less than 100 rpms. Check out this calculator, it works great. http://www.grimmjeeper.com/gears.html