# Chevy 2500 Hd Tow/haul Button



## Jacko (Feb 14, 2005)

Hey all,
Hope everyone is doing well. Let's go camping!!! Anyway, does anyone out there have a 2500 chevy HD with tow/haul button? Do you use it. I'm told I don't need it to pull my 28BHS. I think the saleman informed me if I'm within so many lbs of the conbined weight to include TV/TT--then you don't need it. The truck pulls with no problems, as long as you keep gas in it--ha ha. with or with out the button. 
Any help would be nice.

Thanks
Jack


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## Highlander96 (Mar 1, 2005)

Jacko,

The only thing the Tow/Haul button does is change the shift pattern. I have tried towing with it on and I get better performance with it off. Our 21RS is just too light. I think the manual says that you do not need it until you reach 75% of you GCVW? I do not have the manual in front of me, but I am pretty sure the number is 75%. You know what, I am not sure if it is GVWR or GVW of the trailer, which for my truck would be 9375lbs. (75% of 12,500lbs) We are running half of that.









I'll check and get back to you. action

Maybe Fire44 can chime in......He sells the things!!!

Tim


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## Castle Rock Outbackers (Jan 18, 2004)

I have a Yukon XL 1500 that has tow/haul mode button. When I engage mine, small flames spray from the exhaust pipe as the motor taps into nitro-glycerine tanks that are mounted next to the battery in the engine compartment. The available horsepower gauge jumps from 285 to 425, and the torque gauge moves from 325 to 500. Really makes a difference for us when towing up Colorado mountains.

Randy


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## tdvffjohn (Mar 10, 2005)

Nitrous on a tow vehicle, cool


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## HootBob (Apr 26, 2004)

What no Blower???

I use the tow mode button on our Armada.
It holds the shifting pattern alittle longer.
Don


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## jallen58 (Oct 27, 2003)

The tow haul button does more than just change the shift pattern it also removes some of the torque management that the computer has. I've seen this on printouts from an on board diagnostic computer. Gm has put a lot of torque management in the ecu (engine control unit) to save wear and tear on the drive train this is what accounts for the poor gas mileage. There are places that can reprogram the ecu to give you better performance and fuel mileage. A friend of mine had his reprogramed and gets 2-3 mpg better and much more power also when its in tow haul even more torque management is removed to give you more power when you need it. As for mine on flat ground I don't notice much differance with or without tow haul however in the mountians there is a big improvment with tow haul.

Jim


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## RCColby (Oct 12, 2004)

I use it most of the time when towing my 5er, the engine does not lug down as much. I also like the engine braking when I am slowing down. Of course with my Durmax I really don't need the extra power!
Bob


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## jgerni (Nov 10, 2003)

On our Suburban it hold the shift pattern longer and tightens up the suspension since it has the autoride feature.

On our 2500HD with the Allison it changes the shift points and allows the torque converter to lock up in 2nd, 3rd, 4th, and OD. Since the TC is locked up in all but first gear, this will also greatly increase the engines ability to slow down the truck on a steep downhill. AKA the Allison grade braking feature.


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## Fire44 (Mar 6, 2005)

From what I have heard from GM the proper way to tow is to engage the tow/haul mode on the transmission and drive with the transmission in overdrive. We towed our 27RSDS to Florida with our 1/2 Suburban and I did use the tow/haul mode and didn't have any problems. I did notice that when the tow/haul mode is on the transmission would not lock in overdrive at any speed under 60 mph. I did learn that if you set the cruise control at 58 mph and then run the speed up to about 65 mph with the pedal and release the pedal, before the cruise control catches and holds the 58 mph the tranmission will lock into overdrive and hold. Don't jump on me yet, I installed a tranmission temp gauge and with the transmission in overdrive and the cruise set at 58 mph we never got over 210 degrees.....
I did notice that when you are running against the wind you can forget the overdrive....

If anybody has any questions please let me know and I will do the best I can to get you an answer.

Gary


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## j1mfrog (Jun 6, 2004)

I use it around town. Off for highway cruising.

From my Suburban Manual: " Tow/Haul is most effective when the vehicle and trailer combined weight is at least 75% of GCWR."


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## RLW7302 (Feb 27, 2005)

I have tow/haul mode on my 2500HD. I use it everytime I tow. I do notice a difference when I forget to put it on. I'm sure that my manual says the same thing yours does ("most effective when ... combined weight is at least 75% of GCWR"). With my 5er, I estimate that I am above 75% when loaded and ready to go.

Happy camping!
Roger .


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## California Jim (Dec 11, 2003)

Castle Rock Outbackers said:


> I have a Yukon XL 1500 that has tow/haul mode button. When I engage mine, small flames spray from the exhaust pipe as the motor taps into nitro-glycerine tanks that are mounted next to the battery in the engine compartment. The available horsepower gauge jumps from 285 to 425, and the torque gauge moves from 325 to 500. Really makes a difference for us when towing up Colorado mountains.
> 
> Randy
> [snapback]36865[/snapback]​


Dang it Randy! ya made milk come out my nose lol


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## Oregon_Camper (Sep 13, 2004)

My therory:

I have = I use it. *

Figured I paid for it, I might as well use it.

Only bad thing is I have to turn it back on everytime I turn the engine off.*


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## hatcityhosehauler (Feb 13, 2004)

I use it on my 1500 Avalanche. I also keep the tranny in 3rd most of the time when towing. Keeps my temps in the 160-180 range all the time except for when taking a grade. Keep the engine rpm in the 3000-3500 range on grades and the tranny stays below 200.

I've been in 1st by the top of a 10% grade outside of Walton, NY (you know the one I mean tdvffjohn) and was making about 30 mph, but my tranny was still below 210.

I would say, you will need to experiment, and see how you like the handling the most. If you find the tranny is constantly shifting in and out of OD, turn it on, or downshift to 3rd. The constant shifting will burn up your transmission.

Tim


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## Joe_650 (Jul 21, 2004)

Since we're on this subject what exactly does overdrive do for you? I have a 99 F150 and I have overdrive. I seen somewhere you should make sure it's off before you tow. I'd just like to know why and what benefit am I getting. I'd also like to know if I should keep it off the whole time I'm towing or just in hilly areas.

Thanks


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## Fire44 (Mar 6, 2005)

When your truck is in overdrive the output shaft of the transmission turns faster that the input shaft, this allows the engine to run at a lower RPM to give you better gas mileage and longer engine life. The reason that it is said not to tow in overdrive is with the engine turning at the lower RPMs the transmission is forced to shift in and out of overdrive to handle any hills or headwinds. The constant shifting can cause the transmission to overheat and we all know that heat is the emeny of a transmission.

With the tow/haul mode that GM uses you can tow in overdrive and it keeps the transmission from the "busy shifting" that towing can cause. When I am towing with my Suburban, I run in overdrive with the tow/haul mode engaged. I have added a transmission temp gauge to moniter the trans temp, but if I feel the transmission shifting in and out of overdrive alot or the temp gauge raises above the 210-220 degree mark I shift the trans back to direct (drive or 3) and the temp will return to normal.

I hope this answers your question...if you need more info please feel free to let me know.

Gary


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## jgerni (Nov 10, 2003)

Fire44, I've had very little luck running my Suburban in OD pulling the 25RSS and from what I've read your 27RSDS is quite a bit heavier. Unless everything is perfect and I hold my head right she just doesn't like to go in so I don't even try anymore.

That 5.3L seems much happier pulling at 2600-2800rpms instead of 1800-2000rpms which is where OD puts it at 65mph.


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## tdvffjohn (Mar 10, 2005)

Side roads, I put it in 3. In the highway that is mostly level I will run in OD, watch rpms and usually when it downshifts then I will put it in 3 to make it stay there until downhill again.

John

My right arm is tow/haul button


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## Jacko (Feb 14, 2005)

Castle Rock Outbackers said:


> I have a Yukon XL 1500 that has tow/haul mode button. When I engage mine, small flames spray from the exhaust pipe as the motor taps into nitro-glycerine tanks that are mounted next to the battery in the engine compartment. The available horsepower gauge jumps from 285 to 425, and the torque gauge moves from 325 to 500. Really makes a difference for us when towing up Colorado mountains.
> 
> Randy
> [snapback]36865[/snapback]​


Hey Randy,
I'm glad someone else has the same problem, I thought something was wrong when I hit that button and all that stuff was going on. Man, I feel better--the wife thougth I did something..Jim, wipe the milk

Thanks


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## luv2rv (Jun 21, 2004)

LOL,

Nah, mine doesn't do all that .... wish it did though.

I generally tow in 3rd with Tow/haul engaged. That's what I've read so that's what I do.

Wayne


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## Humpty (Apr 20, 2005)

California Jim said:


> Castle Rock Outbackers said:
> 
> 
> > I have a Yukon XL 1500 that has tow/haul mode button.Â When I engage mine, small flames spray from the exhaust pipe as the motor taps into nitro-glycerine tanks that are mounted next to the battery in the engine compartment.Â The available horsepower gauge jumps from 285 to 425, and the torque gauge moves from 325 to 500.Â Really makes a difference for us when towing up Colorado mountains.
> ...


........almost choked to death laughing so hard...... not milk though..............


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## Jay (Apr 24, 2005)

Really glad I read this post...learning something. Let's see uf I have it right:
1. Tow in 3rd w/ Tow-Haul on on secondary roads or grades.
2. Tow in OD w/ Tow-Haul off on flats at Hwy speed (interstates and major roads).

I have a 2005 2500HD 4x4, and the dealer told me to use Tow-haul when towing..period!

TV = 9,900 GVWR (GCVW = 10,300)
TT = 9,600 GVWR (6910 dry)
8.1 , 3:73

What does this add up to? There ought to be a simple rule of thumb on towing.


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## hatcityhosehauler (Feb 13, 2004)

From the Manual in my '02 Avalanche

"..The purpose of Tow/Haul Mode is to:
-Reduce the frequency and improve the predictability of transmission shifts when pulling a heavy trailer or a large or heavy load.
-Provide the same solid shift feel when pulling a heavy trailer or a large or heavy load as when the vehicle is unloaded.
-Improve control of vehicle speed while requiring less throttle pedal activity when pulling a heavy trailer or a large or heavy load."

It then goes on to say:

"Tow/Haul is designed to be most effective when the vehicle and trailer comvbined weight is at least 75% of the vehicles GCVW.....The tow/haul ismost useful under the following conditions:
-when pulling a heavy trailer or a large or heavy load through rolling terrain.
-when pulling a heavy trailer or a large or heavy load in stop and go traffic.
-when pulling a heavy trailer or a large or heavy load in busy parking lots where improved load speed control of the vehicle is desired.

"Operating the vehicle in tow/haul mode when lightly loaded or with no trailer at all will not cause damage. However, there is no benefit to the selection of tow/haul mode when the vehicle is unloaded. Such a selection when unloaded may result in unpleasant engine and transmission driving characteristics and reduced fuel economy. Tow/Haul is recommended only when pulling a heavy trailer or a large or heavy load"

So, there you have it, right from the mouth of Mr Goodwrench.

Tim


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