2015 Expy HD tow, but with 3.15 rear end. Why?

Fasttimes

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So my sister has a 2015 Limited Expy and she asks me what it would take to add HD tow to it. I was pretty sure Limited models came standard with HD tow and was sure I had seen a brake controller on her dash. I started digging around and asked her to send me pics of the capacity stickers. I noted a Axle code of "10" and then looked it up to find it has 3.15 gearing. Wait, huh? Why add HD tow package with 3.15 gears? She's wanting to retire and get a camper and was asking if the truck was capable.

Does anyone have towing expierence > 5000lbs with these gears? If she wanted to swap out gears what is an average cost of something like that? And to what size should she go?
 

Boostedbus

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I’m pretty sure the Ecoboost will not have a problem towing 5,000 lbs with those gears. Of course it’s not ideal gears and it’ll most likely search for lower gears on hills, but it should still get the job done .
 

99WhiteC5Coupe

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So my sister has a 2015 Limited Expy and she asks me what it would take to add HD tow to it. I was pretty sure Limited models came standard with HD tow and was sure I had seen a brake controller on her dash. I started digging around and asked her to send me pics of the capacity stickers. I noted a Axle code of "10" and then looked it up to find it has 3.15 gearing. Wait, huh? Why add HD tow package with 3.15 gears? She's wanting to retire and get a camper and was asking if the truck was capable.

Does anyone have towing expierence > 5000lbs with these gears? If she wanted to swap out gears what is an average cost of something like that? And to what size should she go?



I ordered a 2015 Expedition Limited 4x4 and the dealer gave me a copy of the Ford order guide at the time (which was effective on 12/08/14).

I looked at this guide tonight. Here were the options / standard axles at the time for the Limited model (you did not specify if the vehicle was an EL and/or a 4x2 or 4x4 model). These listings are for the standard length model.

Limited 4x2: 3.15 standard (non-limited slip)
Limited 4x4: 3.31 standard (non-limited slip)
Limited 4x2: 3.73 optional (non-limited slip)
Limited 4x4: 3.73 optional (non-limited slip)

Limited 4x2 and 4x4: 3.73 optional (limited-slip / late availability in the model year).

The axle code of X10 was the 3.15 ratio: non-limited slip.

The HD towing package was standard on all Limited models (standard and EL) and included:

- Class IV trailer hitch receiver
- Wiring harness with 4 and 7 pin connectors
- HD auxiliary transmission oil cooler
- HD radiator
- Electronic braking wiring kit
- Integrated trailer brake controler
 
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Fasttimes

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I ordered a 2015 Expedition Limited 4x4 and the dealer gave me a copy of the Ford order guide at the time (which was effective on 12/08/14).

I looked at this guide tonight. Here were the options / standard axles at the time for the Limited model (you did not specify if the vehicle was an EL and/or a 4x2 or 4x4 model). These listings are for the standard length model.

Limited 4x2: 3.15 standard (non-limited slip)
Limited 4x4: 3.31 standard (non-limited slip)
Limited 4x2: 3.73 optional (non-limited slip)
Limited 4x4: 3.73 optional (non-limited slip)

Limited 4x2 and 4x4: 3.73 optional (limited-slip / late availability in the model year).

The axle code of X10 was the 3.15 ratio: non-limited slip.

The HD towing package was standard on all Limited models (standard and EL) and included:

- Class IV trailer hitch receiver
- Wiring harness with 4 and 7 pin connectors
- HD auxiliary transmission oil cooler
- HD radiator
- Electronic braking wiring kit
- Integrated trailer brake controler


Yeah, she's got the Limited 4x2, non-Max, with the 3.15. I guess she can give it a try and see how it works out and if need be upgrade to the 3.73s.
 

Boostedbus

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Yeah, she's got the Limited 4x2, non-Max, with the 3.15. I guess she can give it a try and see how it works out and if need be upgrade to the 3.73s.
Yeah it’ll be way less expensive to change ratios on a 4x2 if needed. If she tows with “tow/haul” selected it will help with staying in a gear it needs to pull the hills instead of shifting constantly.
 

Meeker

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In my humble opinion the 10-speed transmission makes the final gear ratio a lot less important than it used to be for towing. When we had 3-speed C6 transmissions, then yeah you needed that 4.xx rear to keep the revs up at highway speeds. But now, if you want rpms just drop down from 9th gear to 8th gear and your rpms increase... what, 600 rpm or something? The gears are so much closer together now.

Oh snap - just realized you're talking about a 2015. Is that a 6-speed? The rationale might still apply but you'd have to adjust highway speed to keep the rpms in a comfortable range since the ratio gaps will be larger.
 
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Fasttimes

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In my humble opinion the 10-speed transmission makes the final gear ratio a lot less important than it used to be for towing. When we had 3-speed C6 transmissions, then yeah you needed that 4.xx rear to keep the revs up at highway speeds. But now, if you want rpms just drop down from 9th gear to 8th gear and your rpms increase... what, 600 rpm or something? The gears are so much closer together now.

Oh snap - just realized you're talking about a 2015. Is that a 6-speed? The rationale might still apply but you'd have to adjust highway speed to keep the rpms in a comfortable range since the ratio gaps will be larger.
Yeah, it's a 6-speed I believe.
 

JasonH

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Yeah, it's a 6-speed I believe.

It is a six speed. The weight isn't the issue...it's the aero drag. Only thing she can do is drive it and see how it feels. It should be fine on level ground. On hills it might work a bit. Maybe rent a camper. For pricing, call around to off road shops. They should be very familiar with that type of work. The ECU would need reprogramming as well.
 

Frank Swygert

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I pull a 7200# camper with my 2003 Expy 4x4. 5.4L, HD towing, 3.73 axles, four speed trans, rated at 8200# towing capacity. I don't boon-dock so don't carry a tank full of water, but I'm still right at or a bit over the recommended tow capacity. Towing capacity doesn't include any passengers, luggage or equipment in the vehicle or camper. It tows okay. Not going anywhere in a hurry, but it WILL tow the trailer at 70 mph in relatively flat, modest hill terrain. Will lose 5-10 mph going up hills depending on how long and steep. In the mountains it will slow to 40-45 mph in third gear going up inclines. It won't drop to second unless I really press on the gas pedal. Makes more noise and burns more gas, doesn't really speed up much (if any). I don't go in the mountains often, and I rarely drive much over 60 mph. Power to increase speed over 65 mph goes up exponentially due to aerodynamic drag according to tests conducted in the 70s. My Expy, especially with camper in tow, is about as aerodynamic as a early 70s car... maybe slightly more? So I drive 60-62/3 at the most. Gets 8-9 mpg with that load, 16-17 any other time.

A six speed trans would be slightly better towing, but when I bought the 2015 about three years ago it was in better condition than newer models and had just under 100K on the clock! Had been babied and garage kept it's whole life, and the price was right!! I was looking for a 2011-2013 so I could get the six speed, but mileage on all I saw was 125-150K+, price was about $4-6K more, and they looked like 10 year old vehicles. My 03 STILL doesn't look 10 years old, much less 18!!

The rating for the 2015 with Eco-Boost (only engine offered) is 6000# for the 4x2 with 3.15 axle, 9300# with 3.73 gears. Bear in mind that the tow weight doesn't include load in vehicle or trailer. There is some wiggle room, but a good rule of thumb is to allow 1000# for load as a minimum, more if you know for sure you're carrying more (like the water in a tank if boon docking, and weight of generator, etc.) It's just me, my wife, and 50# dog, so I'm pretty good with that, but if you have a couple kids and take a lot of "stuff" with you, you'll want to subtract more -- 1500# might be a better number. So if it's just your sister and hubby, maybe a dog, she will be fine pulling a 5000# camper as is. It won't be something like my three slide 30 footer, more like a Coleman Clipper 21FQS (4695#, but it's a good camper for a couple, but no slides https://coachmenrv.com/travel-trailers/clipper-ultra-lite/). Look at the EMPTY weight, or GVWR (or UVW) listed weight. That should be no more than 5000# for the 3.15 geared 2015 Expy. Limits you to trailers with no slide or a small slide in the 21-24' range. Something like a Forest River Cruise Lite West T197SS (4,113# empty). The larger campers on this site would work:https://www.thewaywardhome.com/travel-trailers-under-6000-lbs/.

Just know what the specs are before looking and look at the sticker on the side with the GVWR BEFORE you even look inside!! No point in looking at something you can't tow without buying another vehicle. You may as well find out what that axle upgrade is going to cost you before looking too -- the larger they are the nicer!
 

GlennSullivan

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So my sister has a 2015 Limited Expy and she asks me what it would take to add HD tow to it. I was pretty sure Limited models came standard with HD tow and was sure I had seen a brake controller on her dash. I started digging around and asked her to send me pics of the capacity stickers. I noted a Axle code of "10" and then looked it up to find it has 3.15 gearing. Wait, huh? Why add HD tow package with 3.15 gears? She's wanting to retire and get a camper and was asking if the truck was capable.

Does anyone have towing expierence > 5000lbs with these gears? If she wanted to swap out gears what is an average cost of something like that? And to what size should she go?
I have a 2017 standard length Expy Limited with HD tow and 3.31 open differential. 20” wheels and tires 36psi front, 38psi rear.
I have no issues at all pulling my dual wheel car trailer with total weight of 6500lbs. She will not have a problem with a 6000lb travel trailer with the 3.15 axle ratio and will get better mileage than the 3.73s. I was getting 12.5 mpg on a recent 1280mi trip from FL to NY.
 
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