Hey ford experts. I just got myself this truck, and I have a few questions I might run by you.... forgive me if they appear strange as I am new to trucks - and towing....
1) Background: Empty and running at 55-60 mph gets me fuel consumption at about 19 mpg (US) {23mpg Can in case I screwed up the math}. When towing a 24 ft 7500 lb 5th wheel (supposedly 1/2 ton towable) which I just bought, consumption increases to 10 mpg - and I DO notice the trailer on start up and steep hills. This to me seems like a pretty extreme drop for such a powerhouse of a truck. Ford just looked at the unit (for ESP purchase) and say there is nothing wrong with it. I also notice that even on relatively flat ground the turbo is running right around 20 psi most of the time while rpm stays between 1500-1700. I felt using tow/haul I was using more fuel (rpm stayed higher longer), and I don't now use cruise control either. T/H will be used for long downhills but when need to reduce speed (e.g. entering a community, rpms stay up there even tho' feels like it should be in a higher gear). Should I be concerned? Should I be doing something different?
2) Will switching to smaller wheels make a difference? any complications with that (other than odometer)?
3) Will lowering the cab/box make a difference? any complications with that (other than ruining the truck's appearance)?
4) Will a deflector over the cab make a difference? I heard mythbusters nixed the idea of a louvered/netted tailgate.
5) Transmission - any way to control OD or D selection? I can use the accelerator to knock it out of OD but have no control on when it shifts up... Should I like this feature?
6) I read somewhere that any time the battery is disconnected, then the transmission has to "learn" its shifting patterns (?) all over again.... sounds arcane to me....
Any help for this far northern newbie, who is neither a mechanic nor so inclined, is greatly appreciated....

 

The tow/haul mode in the transmission is designed to hold the truck in gear longer when accelerating / climbing a grade to avoid shifting excessively and keep the RPMs and speed up. You will see a decrease in fuel economy any time you are towing as there is more of a load on the engine and truck than when it is only moving itself and you. Part of the decrease in MPGs is due to the weight of the trailer but also, as you have already figured out, the wind resistance against the front of the fifth wheel.

You will not be able to go any smaller than 17" wheels due to brake clearance, however, you may be able to go to a smaller diameter tire. I doubt that will net you much of a gain in MPGs though. A wind deflector on the cab may help a little but it's also added weight. I'm not sure how you would lower the cab and / or box but I doubt it would help much.

There is no way to lock out overdrive on the Torqshift transmission. The button on the end of the stalk only serves to engage / disengage the tow/haul mode. When I tow, I use T/H unless I'm on completely flat roadways which is almost never and I actually get better fuel mileage using it. The T/H feature on these transmissions is excellent once you get used to using it. It is also designed to reduce your speed when descending hills. The RPMs will stay up there as the T/H uses the transmission gears to slow the truck and this is normal and nothing to be concerned with.

When the battery is disconnected, the transmission does have to learn it's strategies again. The disconnection of the batteries causes the previous shift strategies in the computer to be erased, so they need to be relearned. This is also normal.

My turbo also routinely shows about 20 +/- pounds of boost depending on my speed, the headwind, and other factors regardless of how level the roadway is. The turbo makes boost to get the truck moving and to keep it moving. Regardless of the terrain, you will see the boost come on from time to time in order for the truck to maintain speed.

From what you're describing, it sounds like your truck is doing just fine. Let the engine and transmission do their jobs. Tow/Haul works great when towing but it takes a little getting used to if you've never had a vehicle equipped with it before. Using it both when climbing and descending hills and mountains will be a big benefit. When you are ascending a hill or mountain, use it. It will hold gears longer and it won't shift as much and you'll likely maintain your speed better. Likewise when descending. Keep it in Tow/Haul. It will help you maintain slower speeds without burning up your brakes.

I'm not sure what Job # your truck is but you might check. Ford changed the front valance on these trucks (the plastic front spoiler under the bumper) during the '08 model year and extended it to a larger size in response to consumer complaints of poor fuel economy from the 6.4. If yours is a Job # 1 truck, it will likely have the smaller valance. You should be able to pick up a newer valance pretty cheap and it may help a little with your MPGs.

 

From what you are describing it sounds normal. I think your empty fuel mileage is a bit high may want to recalculate most get no more than 16 mpg. Your loaded fuel mileage is about right. When towing just leave it in T/H and let the trans do its thing.

 

1. You might want to put your 5th wheel trailer on a scale if you are really interested in what it weighs. Also, weigh your truck. You may be surprised.

2. Your description of the motor "feeling" the weight. Your truck probably weighs 9000lbs., your trailer is probably around 9000lbs. 18,000lbs is a lot of weight to be moving around without "feeling" it. If you have any friends with Chevrolet's or Dodge's see if you can tow your trailer with their truck and compare. I can tell you from experience that your truck is the best there is for towing anything.

3. The transmission strategy is pretty good in tow/haul. Just like what's already been posted. It's designed to help you maintain and control your speed without having to use brakes. The high rpm's in community streets is part of this too. Only time I wish I could lock out O/D is when I have over 14K worth of a trailer.

4. I have a job #1 that came with the small front valance under the bumper. I switched it to the larger one hoping for MPG gains. I do think it helped when running without a trailer, with a trailer there is just too much need for fuel and it's hard to get consistent MPG readings.

5. For your aerodynamic concerns, search the towing forum near the bottom of the Forums main directory. I have read as much as I can find about cab mounted wings, tailgate questions. Nothing really makes that much of a difference, certainly not worth the money to try to outfit your truck with aero and fuel mileage in mind.

 

Your fuel mileage will also get a little better once you have 10-15,000 miles on it...I also have heard of guys reporting even better over 30,000....

 

Thanx so much for your input - we're going camping again this weekend and I will use T/H for the trip (here in Yukon we do have our share of hills). I did expect to lose on the gas mileage, but to half it did come as a bit of a shock to my system. How long does it take for the tranny to relearn it's strategies? I am pretty sure my truck is a Job 1 as it went into service in March 2007, and I will check out the valance - great tip! I am very happy with this unit however. I bought it near Calgary and travelled throughout western Canada and northwestern states before I picked up the 5th wheel and drove it home. I put on 9000 kms (5500 miles) before my wife got to see it.

 

thanx for the tip on T/H - similar to others.... I am definitely getting 22-23 mpg (Canadian) when empty, and that translates to about 19 mpg (US). I am using Cetane Boost; perhaps that is the difference?

 

You can use tow/haul to reduce how often it goes into overdrive. I don't like the lack of control on overdrive selection, Ford thought it wasn't needed.

No, that isn't true.

What the transmission does learn is how long each shift takes from when the computer commands it until the sensors report that the ratio change is complete. The computer uses this data to adjust the shifting pressure on the next shift to make the length of the shift as close to the programmed ideal shift as possible. We thought that was advanced, not arcane.

 

If you want to improve your mileage while towing, you may just want to change your strategy a little bit. If you want to maintain speed as you climb hills, your truck has plenty of power to do it. However, you take a hit in your mileage to do so. What I do is try and maintain a constant pedal pressure and accept what it gives me (unless it is just too slow). After you get to know your truck a little bit, you'll know when you need to increase pedal pressure to keep your truck moving at whatever minimum speed you want it to move at. Back when I used to set the cruise and let it maintain speed, I got about 10 to 11. When I changed my strategy, I get 12-13 pulling 14,000 pounds.

I do not have a 6.4 but I have found with my 6.0 and my previous 7.3 that above 2,000 rpm, the mileage seems to suffer greatly. With my 3.73 gears, that is about 72 mph. So I usually run at no more than 70 mph.

Also, I don't think 20 psi boost is anything to worry about. That seems normal to me.

 

I, through my ignorance, obviously misunderstood what I read - thanx for the correction