I do a lot of city driving, stop and go, under 50mph, with an average of 40mph. With 6500 on the odometer I am getting 12 mpg. I have the 01 F150 Xcab 5.4, auto, 17"rims, 4wdr.

Has anyone tried turning the overdrive off in these conditions to see if it would improve mileage. Is there a way to reverse the logic of the 'off' switch so that the override is normally off and you use the switch to turn it on?

My feeling is that I could be loading the engine because of its low rpm and burning more fuel than I would if I could keep the revs up.

Anybody comments??

 

My very un-scientific test netted me a loss of more than 1 mpg.

 

If you find that you are actually going into "OD" while driving in the city, then I'd say yes. If you never actually get into "OD", then the engine doesn't know the difference.

This is just what I do. I turn off the OD when in the city or in heavy traffic. I've found that it likes to shift into OD when you let off the gas, no matter what speed you are going. When you give it gas again, it shifts out of OD and just adds to the number of shifts the tranny has to do.

I also like it just being in third when coasting down hills. Don't have to keep hitting the brakes. I have no hard facts on whether this makes any difference at all. Just know that my tranny shifts less, so in my mind, less shifting means less wear.........

I also don't do this to try to increase my gas mileage, just to keep the wear and tear down on the tranny. I think the owners manual even says to do this if you find your tranny shifting in and out of OD all the time. You don't really want it shifting in and out 100 times during a 10 mile stretch of road........

As far as the gas mileage you are gettting, I'd say that it's still a pretty new engine and things are still pretty tight. When a friend of mine got his brand new, he was only getting 12 mpg too. After he got over the 10 grand mark and switched to Mobil 1, he says he's getting around 14 now.

 

Haze10
From my own experience I'd say that it won't make any difference, I would think that between the stop-and-go driving and the extra weight of the 4wd that's what you're going to get.

On a flat road O.D. comes it at about 45mph under light acceleration and a little earlier if you lift off the throttle, it won't come in under 40 no matter what you do (unless you're going down hill).

I got about 13mpg when I first bought the truck and now average about 14.9 mpg, although mine is a 2wd and my commute is a mix of streets and freeways (35 to 65 mph).

You might want to check out this post:
https://www.f150online.com/forums/sh...threadid=59853

 

Save your tranny turn O/D off all the shifting back will cause early failure

 

I agree with Mitch150 leave your Overdrive off in the city extra shifts equal more wear and heat buildup, I dont think you will see a big difference in gas mileage. I like you drive in the city everyday (Washington D.C.) and when I reach the city I turn my overdrive off I also put the transmission in 2nd gear because most of my city driving is under 30mph this way there are no upshifts or downshifts because the transmission starts and stops in 2nd gear.

 

I did't know that about 2nd gear thanks 360 I'll remember that the next time I'm downtown.

 

Sorry, JAFS360, but I've got to disagree...

Keep in mind that your tranny was DESIGNED to start out in first gear, then upshift accordingly. It was not designed to start out in second gear - that's why second gear is not first. You really are increasing the "wear and tear" on both your engine and tranny by doing this in city driving.

Starting out in second gear in stop and go driving - the toughest type for a heavy vehicle - will cause significant heat buildup in your torque converter, higher con-rod loads due to high torque/very low rpm, and larger throttle openings while accelerating thus poorer fuel economy.

The only practical time to start out in second gear is to help limit wheelspin (via a reduction in torque multiplication) on slippery surfaces, like pulling a boat up a slick ramp.

Just my $0.02

 

You guys have me confused….If your in 2drive, doesn’t the truck start out in 1drive then shift into 2drive and stay there??????

 

I haven't noticed with my SuperCrew but my past Fords start in 2nd and stay there when set on 2. It works very good for starting out on ice or slick conditions. G.M s start in first and go to 2nd.

 

Putting it in 2 on my truck starts the truck out in 2nd. Like others have mentioned, I only use this when traction is limited, like snow and icy roads at intersections. It is a nice feature to have in an automatic tranny and a 2wd truck in the snow belt!

I also agree putting it in 2 in the city all the time is harder on the truck than putting it in drive with OD off. Sure, you aren't shifting in and out of 1st, 2nd, and 3rd, but think of all the things going on in the tranny which will create heat, just like constant shifting under load will. And you are harder on the throttle, meaning a reduction in fuel economy.

Its not like these auto trannys have a granny low first like many truck stick shifts have. There it is fine in many cases to start out in 2nd, but not on an Auto.

 

RobBobster

I think we will have to agree to disagree on this subject, the main reason I practice this 2nd gear only routine in slow city traffic is to reduce the constant 1-2-3 up and down shifting common to this type of driving. It is my opinion that the constant shifting will cause more heat and clutch/band wear in the transmission than starting the truck out in second gear will. My truck is equipped with the heavy duty cooling package including a transmission cooler which should more than make up for any extra heat buildup (which I believe is minimal) caused by starting the truck out lightly in 2nd gear, also shouldn't the torque converter slip less at idle (not moving) in 2nd gear than in 1st.

Simply my opinion!

Anyone else have an opinion on this subject?

Everyone have great Holidays!

 

Nope. You are going to get more slip at idle.

To illustrate, consider trying to hold a manual transmission vehicle steady on a slight incline, using only the clutch, in second or third gear. What do you have to do to? Slip the clutch more than you would in first gear. A LOT more. Same thing applies to your autobox truck. Higher gear, low/no speed = more slip.

What you are doing, by starting our from a stop in second gear, is causing more wear than you realize. The very clutch/band wear you are trying to avoid is, in fact, happening at a far greater rate than simply starting out in first gear.

While your tranny cooler will help keep things cool, it does nothing to reduce the increased wear you are putting your rig thru. Tranny wear is one thing, but the lugging of your engine takes its toll in increased con-rod loads, con-rod bearing wear and longer-duration cylinder pressures. All of these things are BAD.

There are some vehicles on the market that are DESIGNED to start out in second gear (Mercedes-Benz trannys used to do this for fuel economy at light loads only). But Ford's aren't among those automakers that do this.

Not to sound like a smart-a**, but I really wish you luck with your driving style. You have every right to your opinion, and that's what these forums are all about.

But if you really consider the mechanics of automotive drivetrains, you'd have second thoughts. Light-load shifting causes insignificant wear on your tranny. Lugging your engine causes increased wear on your engine and tranny.

You've got an automatic - let it do its job. Automatically

I really hope others who also have engineering backgrounds would chime-in here to offer you further evidence... I can guarantee you that none will recommend this particular techique.