I found a truck with the above engine/trans/axle combo and am wondering if anyone can give input on it? I currently tow with a '97 F 250 heavy duty 4wd with a 5.8 E4OD auto and a 3.55 rear end. The F250 drags around whatever I want and gets the job done. Mostly it will be an equipment trailer with hay or assorted stuff on it below 5,000 lbs, once in a great while I'll have a tractor loaded on which will approach 8,000 lbs and more often a 2-3 horse trailer. The preferred trailer I am looking for is a gooseneck 3 horse slant with tack storage up front.
Like I said the F250 I currently have gets the job done with a whopping 9 mpg loaded and 12 mpg empty. It is not a daily driver as I have a Ranger for that, but if I get a new truck it will replace both of my current trucks, I would prefer a 3.55 rear end on the ecoboost but the supply of leftover 2017's is getting pretty thin and the mentioned combination is available.

 

Test drive it

 

From what I have driven different trucks I am sure it will be peppier, more responsive and run lower rpm's at all speeds than my current old F 250. But if I hook up 7000 lbs worth of horses and trailer to it will the extra gears of the 10 speed transmission make up for the higher rear axle ratio?

 

I would get the max tow package if you can find one. That package will include 3.55 gears, a trailer brake controller and a transmission cooler.

 

There's lots of great towing information on page 289-298 of the 2018 F-150 owners manual http://www.fordservicecontent.com/Fo...US_05_2017.pdf

 

Dont mean to offend here with my reply guys. I have '17 fx4 lariat with this new 10 speed. I bought it as it's supposed to be a great tow vehicle. So far it's the worst I've ever had. Always had gm. When your riding without towing the gears always in 10 th giving you a thumping sensation. Gear too high for the speed. That autoshut off button is a PITA. Towing a 20 ft pro v can really feel the thumping (even in tow haul) towed my 23 ft vnose sled trailer yesterday and it was pathetic. Do yourself a favour get a normal f150 without the 10 speed tranny. I'm getting rid of mine this week. Hope that helps

 

I have the 6sp trans with the 3.31 axle and have towed in excess of 5000lbs through western Colorado through the mountains and never had any issues. Well, cooked the brakes but you didn't ask about that. :-)
I would think the 10sp would only be better but haven't looked at the individual gears.

 

If you can see the trucks manual it will show you...

 

Lock out the upper gears! the 10 speed is for unloaded fuel economy. Heck I lock out 6th on my 2015 3.5 eco when towing a load!

 

I'm sure that truck with 3.31s would handle your load just fine. The 3.5L EB makes more torque than the 6.8L V10 did in its first iteration, and it has a LOT more gearing behind it with the new 10-speed.

In fact, you have significantly more gear multiplication with all that torque than my V10 did with 4.30s.

2018 F150 - 4.69(1st gear) * 3.31(Diff gear ratio) = 15.24
'99-04 Super Duty - 2.71(1st gear) * 4.30(deepest gears available) = 11.65

And your engine makes 45 ft-lbs MORE than the old V10 that's more than twice its size.

 

It's absolutely amazing the power and economy we are getting out of our engines now!!

 

I'm sure the lower gear ratios have been changes ever so slightly in the newer 10 speed transmissions but if you are going to do any hauling or towing I would recommend a 3.55:1 ration gears. I haven't done any towing or hauling yet with my 2018 F-150 Platinum FX4 with a 3.5L Ecoboost and 10 speed with 3.55:1 gears but it certainly getting some great fuel mileage thus far. I haven't even gotten through the first full tank of fuel yet and the truck is getting 23 to 24 average MPG in town driving.

One other considerations as well. If you are like many others and decide to put larger tires on your truck, you surely should not consider 3.31:1 gears. Just saying!

 

I am considering a new 2018 F150 Crew Cab Lariat. It looks like with the 3.5 V6, the two axle choices are 3.31 and 3.55.
Can there really be that much difference in fuel economy between the two? I would be towing an enclosed 14' cargo trailer, (7000 GVWR).
Also I looked at the chart mentioned in the owner's manual, and I'm confused about the "3.5L 10.5:1 CR" data. How does that differ from the 3.5L GTDI?

 

You're talking static compression, which is simply the ratio of measured physical volume with the piston at BDC and TDC, nothing more. It is completely irrespective of manifold pressures.

Dynamic compression and actual cylinder pressures vary significantly between the two because of size, which has nothing to do with the static compression ratios.

 

I would not ever be putting larger tires on it. Stock size is just fine for me, not a serious off roader and I’ve got no ego to feed with bigger tires.
It will be a hay and equipment hauler, horse trailer puller, drive me to work and on hunting excursions.