The 2011 F-150 book from my local dealership; in the technical specifications under the "conventional towing -maximum loaded trailer weight ratings" for the 3.5L Ti-VCT 4-Valve EcoBoost it lists towing capacities for axle ratios of: 3.15, 3.31, 3.55, 3.73, and 4.10. If you'd like the phone number to the dealer so you can talk to them let me know. The truck had 3.31 gears, and I don't know what else to tell you.

 

Here I thought we were have a rational discussion. This post kind of seems like I pissed you off (of course I cold be mis-interpreting what you wrote also). That was not my intention. I was merely pointing out what is listed on Ford's website.

 

If you go on the Ford website and configure a XLT screw with EB and 4x4 it's a 3.31 axle...

 

Base axle 4x2 ecoboost is 3.15....with 4x4 its 3.31

 

Yes! Thank you for the clarification! I was frustrated and that was my problem. I didn't know the exact answer and I really didn't care but yet I was the one being asked. (I didn't have to reply, that's why it was my problem :-)) All I could do was find a small scrap of evidence to prove their existence. That's all my post intended, nothing to the nature of "up yours here's proof..."

Sorry for the confusion and thanks again for the help!!!

 

That makes sense, since I wasn't looking at the 4x4s. Thanks for the info.

 

the 3.31 rear end is offered, but only without limited slip... if you want limited slip you have to step up to a 3.55

 

From the order guide:

Non limited Slip 3.31 is standard on Eco 4x4.