Plan to tow a trailer that's 4500# dry and 6500# gvwr. Looking for an EcoBoost F-150 (2011-14). Any recommendations on which rear end? the 3.55 is more common. I live in the northern Rockies.

 

If you can find the 3.73, I'd go for that. But the 3.55 option isn't significantly different honestly. You're talking very very small RPM changes especially on the highway.

 

This subject has come up a lot lately. And I think, I've seen that there is a 4% difference in RPM.

Unk Bob

 

If you plan on sticking with stock sized tires, the 3.55s with an ecoboost will be plenty.

 

Id try to find 3.73s, since you live in the rockies. but 3.73s isnt common. Max tow has 3.73s. otherwise get 3.55s

 

Fx4 very often have 3.73.

Not sure why, but they are more common with that package than any other.

 

I have the 3.73 gears with 3.5 ecboost KR,4x4,SC, max towing package. I pulled a full size cadallic on a 6 ton equipment trailer and was impressed but the best mileage I can get is 15-16 average mpg empty mixed driving. I love the "boost" can't seem to find the "eco" thou......