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Peteandsharon
04-01-2010, 05:00 PM
Hi all, I've only towed with my 2008 F250 for one season and it was primarily in the very flat Wisconsin area. I was just wondering about the tow-haul mode on these trucks. I think I understand the concept in that it primarily changes the shift patterns but I was wondering how some of you felt about the feature. Do you use it? Do you automatically use it when towing or just in hilly areas? Does it seem to make any significant difference that you can feel? Does it hurt fuel mileage that you can tell?

I'm taking a longer trip this summer down to the Oklahoma/Texas area so I'll get my opportunity if I choose to do so. Any information would be appreciated.

Thanks in advance,

Pete

TXBobcat
04-01-2010, 05:28 PM
Hay Pete
I have a 2006 F250. Tow/Haul is great. When towing I use Tow/Haul when I am in the City or heavy traffic. It helps you slow down fast...

If your in a real hilly or mountains area you should probably use the Tow/Haul. It keeps the RPM's higher and the Torque Converter locked. The more you move the oil in your transmission the cooler it will be.

If your in Tow/Haul and your speed increases up above about 63 MPH it automatically goes into OverDrive. If you slow down below 60 MPH your Tow/Haul is active again.

If you leave it in Tow/Haul and going below 60 or so MPH you will get a lower gas mileage because the engine is running at a higher RPM than it might otherwise run out of Tow/Haul. I don't normally use it on the normal Interstate unless your in Montana, Wyoming, Utah or Idaho.

Trust me, if you hit the brakes pretty hard you may have a nose imprint on the windshield.

If you have any specific questions let us know..

BC

Bighurt
04-01-2010, 05:36 PM
You should always use tow/haul when the vehicle is equipped while towing or hauling near GVW/GCVW (3/4 capacity). The tow haul button changes the shift points, this allow the tranny to work easier and last longer. By raising the rpms it increases fluid pressure which dissipates heat during slippage, slippage occurs during the shift in gears. Some manufactures say it locks out overdrive others the shift point is just a precentage higher and at a higher speed, such that they will never get to it while towing. I myself have an 08 F350, but for the life of me can't remember what the manual says.

You can override overdrive by just selecting 3 (or equivalent) on the column. Even when not towing I avoid overdrive in hilly areas cause its annoying I just slow down and downshift from D to 3.

2010augusta
04-01-2010, 05:36 PM
I have the truck in my sig, and I use Tow/Haul every mile that the trailer is hitch to the truck. It might hurt the fuel mileage a bit, but in my mind a couple gallons of diesel is cheaper than a transmission service or re-build.

branson4020
04-01-2010, 05:44 PM
I agree with Alan. Every time I hitch up the trailer, I put it in T/H mode, turn on the integrated exhaust brake (I have a Dodge) and forget about it.

tmcran
04-01-2010, 06:08 PM
If I'm towing- I'm in T/H

jnbhobe
04-01-2010, 08:26 PM
I use tow -haul anytime I am hitched up, I like it for the stopping power the transmission gives. The only time I take it out is when I want OD under 55 or 60 mph. My speeds are a little different because of the 4.30 gears. JON

rick_debbie_gallant
04-02-2010, 01:40 AM
2009 Dodge 2500HD. 6.7L TD, 6 speed automatic with standard exhaust brake. We drove from Texas to New Orleans up the Natchez trail to kokomo Indiana then on to Michigan. Averaged between 10.9 and 12.2. We had the T/H button lite, and drove in 5th gear all the time plus used cruise control. When not hitched and loaded for the winter I am getting between 20 and 23 mpg. I am still waiting for the truck to break in. Only have 15,000 miles on it right now.

Duramax1
04-02-2010, 12:11 PM
I am not convinced that leaving your transmission in tow haul mode, when towing, reduces your gas mileage.

I base this opinion on simultaneously observing the readouts on two different guages that I have on my truck.

Yes, your rpms do increase which would suggest that your gas mileage would be reduced but let me explain about the two guages I have on my truck.

I purchased an after market accessory called Scan Guage which plugs into the trucks computer module that the service departments use. Without going into a lot of detail as you can find that at the internet site, this device enables me to simultaneously see the read outs for:

1. instantaneous gas mileage
2. percentage throttle being used

My visual experience in turning off the tow haul mode when observing those two guages is that the instantaneous gas mileage decreases and the percentage throttle being used increases. I should mention that I do this experiment while using cruise control.

Intuitively I believe then that turning off the tow haul mode does not necessarily decrease gas mileage.

A simple analogy is when you ascend a hill. If you depress the gas pedal, your speed and rpms may not increase but your gas mileage is certainly on the decrease. When you shift down a gear, your rpms increase but you are able to back off on the gas pedal if you maintain the same speed.

I therefore always leave my transmission in tow haul when pulling the trailer.

Peteandsharon
04-02-2010, 02:28 PM
So..... what i'm hearing is that it is pretty universally liked. But let me make sure I understand here. I am now on the interstate and cruising along at 65 MPH which is where I typically max out. My understanding is that at this point, there should be no difference. I should be in OD with the torque convertor locked. It's only in getting up to cruising speed that the tranny would act differently in tow/haul. Do I have this correct? I had a Chevy with the old 6.5L diesel years ago and they flat out said not to tow in overdrive. I wouldnt want to go back to that scenario with the RPM's running that high constantly.

2010augusta
04-02-2010, 07:15 PM
I believe you are correct, when cruising in the highways at 60-65 the RPMs should be the same. With T/H on as soon as I touch the break the tranny will down-shift. I think it does a better job staying in one gear too, and not "hunting" when you are near a shift point.

rick_debbie_gallant
04-02-2010, 09:21 PM
One thing additional comes to mind. That is the "sweet spot". I have heard that on my vehicle the sweet spot is right at between 1800 and 2000 RPM. Which for me is right around 60mph. even though it is an automatic I still think that you can lug the engine by driving in OD (6th gear) and not have the braking power of the engine if T/H is off. That and the exhaust brake is the way to go. T/H on, 5 th gear (for me and my Dodge) and exhaust brake on.

JonDaytona
04-07-2010, 08:22 AM
So..... what i'm hearing is that it is pretty universally liked. But let me make sure I understand here. I am now on the interstate and cruising along at 65 MPH which is where I typically max out. My understanding is that at this point, there should be no difference. I should be in OD with the torque convertor locked. It's only in getting up to cruising speed that the tranny would act differently in tow/haul. Do I have this correct? I had a Chevy with the old 6.5L diesel years ago and they flat out said not to tow in overdrive. I wouldnt want to go back to that scenario with the RPM's running that high constantly.
The 6.5's had the 4L80/E (depending on the year I guess) trannys that were recommended not to be used in O/D while towing. However, my dad has owned his '96 Suburban since new and has NEVER hauled without O/D and now has 130k miles without problems. Now with my truck, that has the Allison tranny, by using the Tow/Haul button it does NOT lock out the overdrive. Therefore, while towing a load under 50mph I will use the Tow/Haul feature, but not if I'm cruising on the expressway (in Michigan that is). I think it's personal preference, but should at LEAST be used during slow/stop and go driving.

porthole
04-07-2010, 11:58 AM
At least with the GM D/A combo if you are going to tow, use the Th mode.
It locks the converter from 2nd - 6th gear and keeps it locked. Locked converters generate less heat and use the diesels torque more efficiently.

Locking the converter aids in engine braking. When not is TH mode if you in a gear that the converter is locked, the moment you take your foot off the pedal the converter unlocks. This keeps the deceleration smooth and not as abrupt.

Think about it like this.
Manual trans crusing the highway. Your take your foot off the throttle and the truck markedly slows down and you "feel" it
Do the same but now also push the clutch in. The truck still slows down, only it takes longer to slow and you don't "feel" it as much.