What are the advantages and disadvantages between these features. This will be my first 4x4. I understand the 3.55 gear will be better for towing (torque) and get less gas mileage but am I able to lock the rear axles with a push button on the electronic? Would this also be what you would want if you were stuck in the mud? I don't think I will tow more than 10k so I'm trying to understand if I should order the mid trailer tow package ($895 MSRP) instead of the Max tow ($1195 MSRP) and keep the standard 3.31 with the 3.5 Ecoboost. Same questions about selecting a payload package.

3.55 Electronic Locking Axle Ratio
3.31 Non-Limited Slip Axle Ratio

 

I may stand alone on this, but IMHO if you're towing upwards of 10K, I would recommend the Max Tow option. MPG's will suffer but the power will be there when needed.

My 2011 with the 3.31 axles is rated to pull 9200 pounds and it gets better with the 2015+ trucks but................

 

I also agree with this. If you're routinely pulling that much weight I think you need the max tow for long term durability.

 

Yup, the E-locker will lock both axleshafts together by pulling the 4WD switch outward. This can only be done below 20 MPH and isn't recommended on dry pavement. Stuck in the mud is a good time to use this.

I'd recommend the 3.31s as well. You'll get better fuel economy while unloaded and still be rated to tow 10,700 lbs. The short first gear ratio of these 6-speed transmissions negates the need for short axle gearing, you'll have no problems starting 10,000 lbs uphill with 3.31s.

 

Think you guys misread the OP.

 

I went with Max Tow and I don't tow over about 7,000 lbs. But the truck will be carrying 4 adults and a child plus lots of luggage and gear, so the combined weight will be over 8,000 lbs.

Max Tow got me the bigger 9.75" differential, which has a larger carrying capacity IIRC, a larger tranny cooler, and the 3.55 e-locking gears. That gave me the comfort that I would have enough capability to do whatever I wanted, reliably. And, with the e-locker, if I have wheelspin coming up a wet boat ramp I can push a button and have instant traction. So, yes that's the diff you'd want if stuck in the mud.

 

Just for what it's worth, the 3.5L EcoBoost engine is what got you the 9.75" axle, not the max tow package. And I can't find anything that suggests the transmission cooler is any different with the max tow trucks, but of course the spec sheets aren't always correct.

The previous generation trucks used to have a larger radiator with the max tow trucks, but the spec sheet shows them all having the same one for '15. Again, this may not be correct, that sheet has been wrong before.

 

I forgot the part about the 3.5 EB getting the 9.75". And if you are right about the tranny cooler, which I don't doubt, then I could see going with the 3.31 gears and doing w/o the e-lock. My MPG isn't as good as I'd hoped, and the 3.55's are part of that.

Part of it gets down to how important MPG is to you vs how important ease of towing is. In my case the truck isn't a daily driver, so MPG isn't terribly important. But the extra 7.25% of torque the 3.55's give will be appreciated on the long pulls over hilly terrain I envision, so I'm happy to pay for more gas now and reap the benefits later.

 

Ours is the 3.31 with the e-locker, and we have the larger differential. We do not have max-tow, as we only tow maybe 5-10 % of the time and none of our trailers are over ~~ 9,000 lb. We've had no issues.

We need the e-locker, and I've used it many times when we get into "gooky" situations. In fact, our baby is looking a bit like a mudder at the moment...

 

I'm in the same camp at the OP. The guys (and gals I suppose) have convinced me to get the "normal" tow package and not the MAX for the increased MPGs that come with keeping the smaller gearing. I rarely tow, but want all the capacity and cooling. The lower gears will pay dividends every week at the fuel pump, vs. maybe a slower tow every few years.

As for the gearing, don't forget if you get the FX4 package you get the electronic locking 3.31 gears. Best of both worlds.

 

My towing frequency is not to often. If I was using the truck for work and pulling a trailer regularly the 3.55 with Max Tow would be an easy choice. I'm also not an off roader so not sure if the extra $$ is warranted for that package. I would venture a guess and say I might pull a trailer 10 times a year and my current trailer is rated at 7K. Most boats I pull will also be less than 7-8K with trailer. I'm not sure I've seen any real world numbers for gas mileage difference on gear ratios. Would 1 mile per gallon difference seem reasonable between these 2 gear ratios?

 

I would guess that 1 MPG would be about what you would see when running light. But, that would depend a lot on your driving style and conditions. The 3.55's give you more acceleration with less turbo/throttle, but more RPM. I'm getting 17.5 average w/o a trailer.

 

I get 18.5 average with 3.55s. Are you planning to go up a size or two on tires? If so, get 3.55s for sure. Do you tow in a hilly area or an area with strong winds? If so, also consider the 3.55s. The 3.55s are also better if your daily drive includes a lot of stop and go driving. Fairly level highway driving with light traffic, then 3.31s should do it.

Making sure that you get the 9.75 axle would be my biggest concern, then the locker if you ever park you trailers in a field or gravel lot and have to pull one out when the ground is wet.

The factory brake controller is better than anything you can buy aftermarket, so consider that as well.

 

Dumb question but again my first 4x4. Does the elect loc do both axles front and rear. Also any advise on payload package?

 

Just the rear.

Cut and past from Ford,

Max Trailer Tow Package includes:

• 3.55 Electronic-locking rear axle
• 4-pin/7-pin wiring harness
• Auxiliary transmission oil cooler
• Class IV trailer hitch receiver
• Smart Trailer Tow Connector (standard on LARIAT and higher)
• Integrated Trailer Brake Controller
• Upgraded front stabilizer bar
• Upgraded rear bumper

Heavy Duty Payload Package Includes:

• 3.73 Electronic-locking rear axle
• 9.75-inch gearset
• Upgraded springs and auxiliary transmission oil cooler
• XL: 17-inch Silver Steel Wheels
• XLT/LARIAT: 18-inch Silver Aluminum Wheels

Now, the Heavy Duty Payload Package forces you to get 3.73 gears and a 6.5' bed on a SuperCrew or an 8' bed on a SuperCab or Regular cab. For some reason, you can not get the center console either. But, if I remember right, you want the center seat and 6.5' bed anyway. Looks like the deal breaker on the Heavy Duty Payload Pkg for you are 3.73 gears.

The Max Trailer Tow forces you to get 3.55s, but includes the brake controller.