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Old 01-06-2010, 03:04 PM   #15
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A friend explained this to me a few years ago. Pretty simple, the pressure plates in the transmission are pretty small for the overdrive configuration and have a tendency to burn out, but the 1 to 1 on straight high gear are much more stronger. He says he always disabled the overdrive on his company trucks to prevent transmission damage by his drivers using the overdrive.

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Old 01-06-2010, 03:14 PM   #16
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tow/haul mode?

I use OD except when towing up a long steep hill or when I'm going too slow. I also have tow/haul mode (a 5 speed Allison tranny ) and a tranny temp gauge. On the previous TV I had none of those features but I tried it once. Biggest result was constant shifting and terrible MPG.

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Old 01-06-2010, 03:45 PM   #17
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08 f150 5.4 4x4- with 04 28 safari. With a console shift I use the tranny to help stop the rig as much as anything by downshifting when possible, even down to 1 to a stop light. I tow in overdrive 100% of the time and let the computer figure it out. I do not have the trans and exhaust temps mentioned previously and I find that very interesting.Time will tell, she has 48k on the clock and all but say 10k pulling the streamer. Trans fluid is original and perfect according to Ford dealer at last oil change. It is making a little whine when cold however in first gear. Other than that a bullet proof vehicle, and my only complaint is the leather on the drivers seat is looking old quick.
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Old 01-06-2010, 04:15 PM   #18
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Originally Posted by safari 28 View Post
. Trans fluid is original and perfect according to Ford dealer at last oil change. .
Gotta wonder if that dealer is trying to sell you a new tranny?!

48K without a change? Whats the owners manual say about that? Much less if 40K of that was under load.
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Old 01-06-2010, 04:19 PM   #19
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Overdrive Never with trailer

I have a new Chevy Silverado 1500 4x4 w/trailering package. It has a transmission temp guage and I find that towing in 3rd rather than 4th is running much cooler. The engine rpms are up a bit but cooler is better. I also get about 2 mph better in 3rd rather than overdrive. My 65 Safari is only 22' and I hardly feel it behind the truck. Most of my "long haul" friends also confirm that trucks pull better when not using overdrive. Something to do with the power band of the engine. Hope my limited experience helps......Tim
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Old 01-06-2010, 05:25 PM   #20
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I always use the tow/haul on my Silverado 2500 HD Diesel and the EGT and Turbo boost plus the 15 mpg hauling our 30' AS (8500 lbs.) say it's the right thing to do. And so does the owner's manual, written by the folks who have to warranty the equipment and pay if it breaks.

My money's on following the owner's manual instructions, avoiding creative alternatives, and enjoying the excellent performance of my heavy Chevy.

That said, what ever works for you has my respect too!
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Old 01-06-2010, 05:33 PM   #21
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Just to add to the comments, I ALWAYS use the tow mode on my 2008 Silverado.

That was NOT the case with my previous truck, a '97 F150. It was a great truck but after pulling my 4500 lb boat 200 miles from the coast, in Overdrive, because I simply didn't want to hear the engine running at the higher RPM, I noticed oil residue on the tailgate. When pulling the transmission dipstick, the fluid was visually darkened and had a burned smell. I immediately had the fluid changed but the damage was done. Ultimately, 6 months later, the transmission failed and I spent nearly $1,500 having it rebuilt (plus an aftermarket auxilary cooler).

Learn from MY stupidity; use the tow mode and save yourself the agony.
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Old 01-06-2010, 06:41 PM   #22
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Thanks to all for the good information. As I have repeatedly found, this forum is the greatest! So far, I have not taken our trailer on any real trips. I have only pulled it 100 miles from the city where I bought it, and then about 50 miles here in the Dallas-Fort Worth area taking it to and from the shop for some needed work and then to its storage place. In those few miles, I have always followed the instructions and disabled overdrive. I feared that my transmission would wind up laying on the highway somewhere if I did otherwise. My truck has an auxiliary transmission cooler, but no transmission temperature gauge. The main things I noticed without overdrive are the additional noise and RPMs and of course the reduced fuel mileage. My RPMs were usually about 1900 on the highway, and pulling the trailer without overdrive I'm seeing about 2300. The highway fuel mileage dropped from about 17 to about 10. The next time I get it on the highway, I might get bold and try overdrive for a few miles. For the first few trips at least, we will be on the "flatlands." In my part of Texas there really aren't too many hills of any consequence. The Rockies will probably have to wait until we get a beefier truck.
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Old 01-06-2010, 10:30 PM   #23
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Overdrive or not?

Hi, Ford says I can tow in overdrive and I do. [on level freeways] Yes everything is computerized and your vehicle knows what to do and when, but I do a lot of manual shifting during up and down hill towing. [overdrive off] Is your trailer too close to your tow rating? [my tow vehicle 8,900 lbs / my trailer 6,300 lbs.] Is your differential geared too tall? [3:73 on mine, lower is better 4:10 Etc] Does your engine have more low end torque? [torque rated at 2,750 RPM] Most gas engines are rated at a much higher RPM] Was your tow vehicle built with the factory tow package? [mine was]

If your engine is too small, your differential too high, [3:55 +] Your tow rating too close or surpassed, [trailer too heavy or vehicles overloaded] and your vehicle wasn't made with factory tow package, you might want to stay out of overdrive.

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Old 01-07-2010, 12:02 AM   #24
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"Overdrive" is becoming a misnomer these days..., because many vehicles of the last decade are equipped with not just one but often 2 overdrives.

"Overdrive" was just another name for the 4th gear in the common 4-speed auto transmission. By turning OFF the overdrive, you disable the 4th gear -- thus forcing the tranny to operate only on the 3 remaining speeds.

4th had become known as 'overdrive', only because 3rd was the 'direct drive' (often with 1-to-1 gear ratio where the engine rpm is equal to drive shaft RPM)

Today, 5-speeds or even 6-speeds auto-tranny are increasingly common. I may be wrong, but I don't think you will find 5-speeds or 6-speeds transmission to have 'overdrive' selector. Anything above the "direct drive" (3rd, or maybe 4th) would be overdrive(s) (4th, 5th, and 6th). It'd be confusing.

Anyway, sorry to digress...

Auto-transmission is at its strongest when engaged in the 3rd/direct drive. This is because the INPUT shaft (the power from the engine) and the OUTPUT shaft (the power to the wheels) are mated to each other directly. In any other speeds whether in lower (1st or 2nd) or higher (4th, 5th, and 6th) must involve severals of reduction (multiplier) gear components.

In 3rd, it involves the least number of metal pieces to transmit engine power.
In others, it involves more number of metal pieces to transmit engine power.

More pieces = more heat and less efficient -> not good for the tranny.

When towing on the flats with the "Overdrive ON", you allow it to engage 4th, and let the engine to operate at less RPM. It's quieter, and you will save some gasoline. But you only achieve that by increasing the wear and tear on the metal components of the auto-transmission...
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Old 01-07-2010, 05:47 AM   #25
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The F150 is equiped with two transmissions one for the 4.6 Litre engine and a much heavier duty one for the 5.4. Your transmission is the same one that is mated to the v-10 in a motorhome chassis and was also used with the older diesels. It was designed to tow in overdrive and I don't think you could ever hurt it with a 5.4.

As well don't worry about traveling to the mountains your truck will climb mountains without a problem, you will need to downshift to second gear occaisonally which is fine and normal. If you think about it your truck has far more power than any tow vehicle we could buy 20 years ago and we still drove all over the mountains.

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Old 01-07-2010, 07:53 AM   #26
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OD vs. Tow/Haul

Be careful to distinguish between over drive and tow/haul mode. I have a new generation Tundra and the tow/haul mode only changes the electronic shift points in the transmission. It does not lock out the high end. It is very helpful for getting things up to speed and also helps with engine braking I have been told. I use it when I am entering roadways and in heavy traffic.

I drive in 5th most of the time but will shift to drive (6th=overdrive) only when I am on the flats. I had an older 4Runner that had an actual OD switch on the gear shift and this would shut out the top gear. Tow/Haul in the Tundra does not do this.

I would not hesitate taking your set up into the Rockies. Just don't be in a hurry.
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Old 01-07-2010, 08:02 AM   #27
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Overdrive is a way of lowering your engine rpm (lugging) while pulling a load, thereby getting a bit better fuel mileage, especially with diesels that work best pulling with low rpm engine torque. The trade-off for this is that your piston/cylinder head temperatures will be higher (sometimes much higher) than if your engine were running at a higher rpm.

In a big truck, say with a 10 to 13 speed transmission where the choice of gears is very flexible, when pulling in the mountains you must have a pyrometer installed to watch your cylinder temperature and know when to downshift so that you don't melt your pistons. I think that lugging an engine without a pyro is risky.
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Old 01-07-2010, 08:09 AM   #28
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The 5 and 6 speed transmissions almost always have only a single "overdrive" gear. The extra gears are in-between, and are created by simply engaging and disengaging the torque converter clutch in the different gears.
As for towing in overdrive, I found our truck ('02 Silverado) gets slightly better mileage in drive.

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