QuiGonJohn

Tow/Haul Button

15 posts in this topic

I have a 2006 Winnebago Aspect 26A on the Ford E-450 cutaway chassis with the V10 gas engine. On the end of my shift lever there is a TOW/HAUL BUTTON.

Can someone explain what exactly it does and how I should make use of it?

Also, if I press it, is there some indicator light that should come on that will let me know it is "ON" so I can turn it off when finished using it?

In other words, I would not want it to be in a state that I cannot tell if it is on or off.

Thanks!

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The "Tow Haul" feature modifies the transmission performance to give you greater control for a heavy load. The shift points will be a bit higher and shifting frequency will be reduced. Also, the transmission will not coast, so the engine will work as a brake whenever you take your foot off the throttle.

There should be a small light, probably on the shift lever, indicating the Tow Haul feature is engaged. Are you sure it isn't there somewhere? Also, each time you shut down and restart the engine, the Tow Haul feature should reset to "off" for regular driving. With that in mind, you will probably need to turn it on each time you start with the load attached.

Please, please check your owners manual to confirm, since my vehicle is not the same as yours. However, you should find that your TowHaul operates similarly.

Happy travels,

Tim

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Tim, I never pressed it, as I was afraid if there was no light, it could be "on" and no way to know if I successfully turned it "off".

So if I am not towing anything, it sounds like the only real use I would have would be to engage it for very steep downgrades, to provide a sort of "engine brake" effect. Does that sound about right.

The MH weighs a bit under 12,000 lbs loaded and I do not tow a vehicle.

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The Tow / Haul button is used to take the transmission out of overdrive in most cases. As mentioned there is an indicator light on the dash that informs you when the system is energized. Helps keep the transmission running cooler when pulling heavy loads.

With it engaged, the transmission allows for more engine braking.

In overdrive when you reduce the throttle, coasting resistance is reduced.

Rich.

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Yes, if you engage the Tow Haul on a downgrade, you will get additional engine braking effect. That is in part due to different transmission settings and part, as Rich indicated above, because the overdrive is disabled.

Tim

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Well I did a lot of research yesterday on this topic, Google which led me mostly to a lot of different RV related forums. It seems there is no real consensus and a wide range of opinions on using the Tow/Haul Mode.

Some people said you should use it all the time, while others said only when you "notice you need it".

Some people thought it would improve gas mileage (less torque convertor slippage), while others said it would lower overall gas mileage if used all the time, (engine RPM would average out much higher, more gas).

I will say that on our trip out to the Grand Canyon, including "mountainess regions" across NM and in AZ, on my MH I did not use it, (I never have used it so far), my MH seemed to handle things well. On uphills it would jump up about an additional 1000 rpm to get us up hills.

And on at least 2 steep downgrades it seemed to adjust without applying brakes, to help keep the speed from running away. I could feel the transmission "change" and the engine noise change and it kept speed under control. This was all on Cruise Control, without the T/H engaged.

So I don't know the best way to make use of T/H. Other than I might try it on an future steep downgrades to see how it differs.

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You will do no harm either using it or not using it. It is only designed to change the shift pattern programming originally setup for that chassis. It's quite possible that the added weight is enough that the shift pattern you are seeing is the same as you would find with the button pushed. I would suggest that you will not find any benefit to using it on flat terrain, but the next time you are headed into an area with some hills you might want to push the button and see if you like (or notice) the change. It's nothing that you would ever be required to use but it might improve your climb or descent experience.

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The fine print of your owner's manual might help. I had a 3500 Chevy dually with the Duramax. The manual said to use the T/H mode when the GCW was 75% or more of the GCWR.

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If those are really the instructions, they are terrible instructions. On flat, level terrain you would never use the T/H option.

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This is what my book says:

With TorqShift® transmission, select Tow/Haul Mode to automatically eliminate unwanted gear search when going uphill and help control vehicle speed when going downhill.

I use it when in the mountains.. Saves the brakes...

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Go ahead and push it, you will be able to tell if it is in T/H or not. You can do this when siting in place so you can look for an indicator light. I have a Chevy truck with a T/H button and it stays depressed till you push it again.

Bill

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I tried it recently going up, and then down, the Skyway Bridge in Tampa. A light comes on on the end of the shift lever. Didn't notice much difference in performance, maybe a bit more speed control on the down hill. But my cruise handles that pretty well, also.

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Had a 2005 F350 King Ranch pulling a 13,000 pound trailer. When the trailer was hooked up, I engaged tow haul. It is a greatly appreciated feature when towing a heavy load. As you found, a light will come on in the dash. Yes, on the downhill side you have a little more help in breaking and maintaining an even speed. I was happy I had it when towing.

Happy trails.

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I use it on my 2009 Allegro when running in traffic with multiple lanes and lots of stoplights. It is great help with braking when someone cuts in front or a stoplight turns red unexpectedly. That's on flat surface by the way.

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Thought I would try to answer the question of the Tow / Haul button for the Chev and Workhorse chassis from the service information on hand.

The Owners manuals for the different chassis manufactures will spell out the operational change of the unit when one engages the button.

The specifications for the drive-trains using the 4L80 or the Allison 1000 series transmissions and what happens internally are a little different.

4L80E series transmission Tow/Haul Mode, Displays Yes or No. This parameter indicates when the transmission is operating in the tow / haul mode. In the tow / haul mode, the PCM commands a different shift pattern that increases performance when towing or hauling. Shift quality and TCC scheduling are also affected during the Tow/Haul mode of operation. One will also notice that this transmission has a tendency to whine, do to the setup used in the planetary gears.

The Allison transmission Tow / Haul mode Displays active/ inactive; This parameter indicates whether the driver has placed the vehicle in the Tow/Haul mode. When this parameter is active, the TCM modifies its shift strategy in order to provide more torque to the wheels during shifting.

The buttons do the same thing, but different modules are involved.

The Chassis manufactures of the P Series Chassis and the Workhorse do spec different transmissions when using the same engine like the 8.1 L GM series.

The Ford RV Chassis using the V10 engine has a Tow / Haul setup from what I understand and most likely works in much the same way, changing the shift pattern and the way the TCC responds to the different switch setting.

Everything regarding the change is controlled by software commands in modules.

Rich.

PCM = Power Train Control Module and it is Electrostatic sensitive !!!!

TCC = Torque Convertor Control

TCM= Transmission Control Module

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