I was reviewing my order confirmation sheet (slow day at work) and found that my dealer put in X31, 3.31 Reg Axle instead of the X3J, 3.55 ratio.

I know I'll get better MPG out of the 3.31 but I'm going to be pulling an 11k gross bumper pull trailer through the mountains. Maybe I'll move up to a heaver trailer some day too. How big a deal is this going to be? I'm going to call my dealer and see if it can be updated, but I already have a build date that is less than 2 weeks away.

 

I really don't think it wil bother you at all.

 

You'll be fine in my books, and I don't think you'll mind. No way they can change it at this point without re-ordering. The list of things you can't do with 925 foot pounds is smaller than the list of things you can do, regardless of how you build it (-=

 

My buddy took a truck off the lot that had a 3.31 rear end and he has come to regret it. We have similar heavy trailers (19K) and he gets 8 mpg regularly. I always got 10.4ish when I towed. We ran exact same tires (Toyo MT 315/60/20) and the only difference between our trucks was that he had 10 inch wheels and the wide fender flares. We both figured that the main reason for the difference in mileage was due to the rear end. He couldn't stay in 6th gear when I could. If you stay with the factory tires it's less of a concern as larger tires will exacerbate the taller rear end.

 

My 2011 was the 3:31 plus I put larger tires on it. I later tuned it but even before that I pulled our telehandler around to load hay. The loader itself weighed 20,000 not to mention the trailer. It did fine even in the hills

 

To clarify, my friend never complained about lack of power, just the mileage. We could roar up long mountain passes with plenty of power to spare. We had the 400/800 trucks which is very different than the 2017 ratings.

 

I too have a fleetwood Gearbox but mine is a 5th wheel. Easily 13k loaded. the 3.31 tows it great.

 

I would make them change. 3.55 will out perform 3.31 everyday. Possibly, but I don't think so, that 3.31 may eek out some mpg gain in a Ford controlled location and surely not loaded or towing.

 

Dealer says the order can't be changed. Bummer. Now I'm going to worry about it.

 

Bottom line, if the dealer ordered it wrong and your not happy, make them honor it. You don't have to accept it.

 

I handed the dealer my list of options. He entered them. I reviewed the order, but missed the axle ratio. I signed the order sheet. I'm as culpable as he is. If this was a difference between 3.31 and 4.30 I would be willing to give up my $1,000 deposit. I can live with 3.31 and hopefully the truck will be so great that I'll forget about the axle ratio completely.

 

i'd have it changed myself.

 

The dealer just responded that he would check to see what it would take to make the swap at the dealer. Sounds expensive to me.

 

The more weight you add for a trailer the more gearing you will want over the long term.

 

Yeah, I know. That's why I had intended to get the 3.55.