Tow haul transmission mode

[bobblangley]

I was told my the service manager at our local RV service shop to NEVER to my trailer unless my transmission is in tow/haul mode. I'd like to tap the collective brain and experience of the group about this.

Apparently, in tow/haul mode, the transmission locks into direct drive so there are fewer moving parts under stress.

I am towing a 1995 Bigfoot 17G trailer (approx wet weight 3000#) with a 2002 Chevrolet HD 2500 diesel pickup that hardly knows the trailer is behind it. I'd like to at least drop into overdrive when cruising on flat ground at 55 - 60 mph but am reluctant to do so based on advice given.

Any thoughts on or experience with this will be much appreciated.

[WizWid]

Originally Posted by bobblangley

I was told my the service manager at our local RV service shop to NEVER to my trailer unless my transmission is in tow/haul mode. I'd like to tap the collective brain and experience of the group about this.

Apparently, in tow/haul mode, the transmission locks into direct drive so there are fewer moving parts under stress.

I am towing a 1995 Bigfoot 17G trailer (approx wet weight 3000#) with a 2002 Chevrolet HD 2500 diesel pickup that hardly knows the trailer is behind it. I'd like to at least drop into overdrive when cruising on flat ground at 55 - 60 mph but am reluctant to do so based on advice given.

Any thoughts on or experience with this will be much appreciated.

Towing my 2002 Bigfoot 17CB with a 2017 Dodge Durango. It doesnt have a tow/haul switch. It just does what it needs to do.....

[bobblangley]

Originally Posted by widgetwizard

Towing my 2002 Bigfoot 17CB with a 2017 Dodge Durango. It doesnt have a tow/haul switch. It just does what it needs to do.....

I think newer trucks like yours have much "smarter" transmissions.

I've heard that newer trucks have software that can correct the speedometer automatically if tire size/height is changed.

[jerrybob]

No offense to your service manager but....he's giving you bad advice. You can tow without tow/haul most of the time....some folks never use it. Your rig can easily handle your trailer. I rarely used tow/haul with my 2003 Chevy 2500HD....only in mountains where the tranny was shifting/searching too much. It does change the shifting patterns. I suggest you read your owners manual. You can feel comfortable not using tow/haul most of the time. I recently got rid of the Chevy and bought a new Ram 1500 with a 5.7 hemi and 3.92 rear.....these new trucks have an 8 speed tranny and are computer controlled.....I have tow haul but have not engaged it yet....except to play.

[AC0GV]

Originally Posted by bobblangley

I was told my the service manager at our local RV service shop to NEVER to my trailer unless my transmission is in tow/haul mode.

Do not go by information from RV service managers. Read your tow vehicle owner’s manual. Some may do nothing more than lock the transmission out of overdrive, others may go to a new program of computer control of the shifting pattern as well as adding more engine braking. On mine, I have also found that tow/haul works well on back roads in the hills even when not towing.I just wish mine would stay in tow/haul when restarting the engine, I often forget to re-enter the mode until I an up to speed on the highway.

[ThomasC]

Originally Posted by bobblangley

I was told my the service manager at our local RV service shop to NEVER to my trailer unless my transmission is in tow/haul mode. I'd like to tap the collective brain and experience of the group about this.

Apparently, in tow/haul mode, the transmission locks into direct drive so there are fewer moving parts under stress.

I am towing a 1995 Bigfoot 17G trailer (approx wet weight 3000#) with a 2002 Chevrolet HD 2500 diesel pickup that hardly knows the trailer is behind it. I'd like to at least drop into overdrive when cruising on flat ground at 55 - 60 mph but am reluctant to do so based on advice given.

Any thoughts on or experience with this will be much appreciated.

I would poke around on a Chevy forum and see what that crew has to say rather than rely on a service manager. From my experience as a lifetime dealer mechanic service managers may not be the best source of information.

[Jon in AZ]

According to the OP, the advice was given by a service manager at an RV shop, not a Chevy dealer. Take it with a whole shaker of salt. Check your manual and/or confer with a Chevy service manager, or better, their shop diesel specialist.

I have a Chevy Express 3500 Class B we sometimes use to tow our 13’ Scamp. It’s a 6.0L gas V8 with a HD 6-speed. The trailer is not heavy, but the motorhome upfit is. I use tow/haul when climbing grades, manual mode when descending, and neither when cruising on flats. In my experience you can tell when a transmission is struggling- frequent locking and unlocking, changing gears... That’s when you want to intervene.

Mine limits top gear to 5th when tow/haul is engaged. It’s still an overdrive ratio. In newer transmissions the whole overdrive distinction is meaningless, anyway. They are just more ratios; they don’t work differently. That was true at one time, but no more.

[Fred762]

WE towed our Casita 17' with our Frontier dbl cab long bed V6 2wd truck for 2 seasons w/o tow mode. About 10,000 miles in 2 yrs... Smokies x several, VT, FL x several, etc etc...

Never had any issues and a couple times we even 4got to hook up the anti-sway bar and could not tell the difference. I guess the old style running gear of the truck (basically the same truck as a 2005)..works ok. We are going to try it this Spring w the heavier Escape 21 we ordered..may have to upgrade to a Nissan full size w V8, but we will see. I really prefer the mid size truck we have..oh well. TDB Nissan does not make the mid size truck w a V-8..that wd B my ideal hauler.

[Sisu]

Good topic. I use the tow/haul mode towing our boat but that system weighs about 6200-6600 pounds depending on what’s in the boat. If I go to one of the two launches close to us that has more elevation gain and loss I’ll use the other tow mode that shuts off the overdrive.


We have a 2006 4x4 2500 Ram Cummins. Towing specs say:
4x4's 325-horsepower 5.9-liter Cummins Turbo Diesel inline6 and automatic combo is rated for 12,400 pounds of trailer.

We just bought an older 17’ Bigfoot so I’m interested as to what Is recommend?

[cpaharley2008]

I have experimented towing with and without the 'Tow Mode" activation. With it activated my transmission does not "hunt" nor down shift at the slightest increase in gas pedal pressure, less wear and tear on the transmission. In addition, going down a grade, the engine brake is activated and there is less use of the vehicle's wheel brakes. Towing without the "Tow Mode" eliminates the engine braking and increases down shifts. My mileage may increase but over 5,000 miles the difference is insignificant. Like Ron Popeil says, "Set it and forget it"....

[Jon in AZ]

Interesting... mine downshifts more easily, not less, in tow/haul mode. However, once it downshifts, it holds that gear longer. Lifting the right pedal does not instantly drop into a higher gear as it does with tow/haul off. That reduces hunting on upgrades.

One thing it doesn’t do well is downshift on downgrades. Firm braking will trigger an automatic downshift, but by then I’m already gaining speed. Manual mode lets me downshift before starting down the grade.

Transmission software is getting better and better, but one thing it still can’t do is predict the future.

[steve dunham]

My truck came equipped with “ Tow / Haul “ mode . The way I see it , the vehicle manufacturer and their engineers put it in the vehicle for a reason .
When I tow or haul , I push the tow / haul button and go on my way
I don’t pretend that I am smarter or know more than the engineers or my vehicles computer .
As far as whether using tow / haul mode affects fuel mileage , I don’t know and I don’t care . If we decide to go on a trip and 2/10 mile per gallon is the deciding factor then I am selling the trailer .

[Timber Wolf]

I used the “tow” mode a few times pulling construction trailers and my Scamp early on. Did not like the MUCH lower gas mileage so have not used the mode in years, and my old (2003) F-150 is still going strong. Have not done anything to the transmission except the regular recommended service. Note that I do not tow really big heavy loads, or over very steep terrain.

[dmad1]

The tranny shop I have used says on the Tahoes, the tranny lines are to small and to increase the fluid flow, try to keep it above 2000 rpm. However, that is hard to do since they have such a high rear end ratio. At 2000 rpm in tow haul (Overdrive?), I am running about 70+ mph.

[Gilles]

Originally Posted by jerrybob

No offense to your service manager but....he's giving you bad advice. You can tow without tow/haul most of the time....some folks never use it. Your rig can easily handle your trailer. I rarely used tow/haul with my 2003 Chevy 2500HD....only in mountains where the tranny was shifting/searching too much. It does change the shifting patterns. I suggest you read your owners manual. You can feel comfortable not using tow/haul most of the time. I recently got rid of the Chevy and bought a new Ram 1500 with a 5.7 hemi and 3.92 rear.....these new trucks have an 8 speed tranny and are computer controlled.....I have tow haul but have not engaged it yet....except to play.

I bought in August 2018 a RAM 1500, 2018, EcoDiesel 3 liters 8 speeds with 3.92 differential, to tow a trailer of about 4500 lbs.
I use the tow / haul option especially in the mountains. It is as effective for ascending as it is descending.
To go up the gears will change at higher speed and to go down, when the brakes are touched at the desired speed, the engine keeps this speed and if the slope is too steep, the brakes must be reused if you notice that the engine hardly remember.
Usually, it protects the overheated brakes ...

[Jon in AZ]

Originally Posted by steve dunham

The way I see it , the vehicle manufacturer and their engineers put it in the vehicle fora reason... I don’t pretend that I am smarter or know more than the engineers or my vehicles computer.

Trust the computer, eh? Like the Tesla driver who drove through a semi-trailer?

Computers can only react to conditions they have been programmed to recognize, and they do that very fast and very accurately. There’s no doubt vehicles are safer and more reliable thanks to electronics.

Still, the human mind is capable of processing way more information in far more complex ways than any computer. I figure most engineers are smart enough to recognize their own limitations- else why provide a manual override feature on the transmission... or the Tesla?

[jerrybob]

Originally Posted by Gilles

I bought in August 2018 a RAM 1500, 2018, EcoDiesel 3 liters 8 speeds with 3.92 differential, to tow a trailer of about 4500 lbs.
I use the tow / haul option especially in the mountains. It is as effective for ascending as it is descending.
To go up the gears will change at higher speed and to go down, when the brakes are touched at the desired speed, the engine keeps this speed and if the slope is too steep, the brakes must be reused if you notice that the engine hardly remember.
Usually, it protects the overheated brakes ...

I agree...there are certain conditions that tow/haul is a good thing.....use it when you need it....otherwise.....go without it. Love the Ram truck....those little Eco diesels are nice....great mileage when not towing. I needed more tow capacity due to a car trailer I haul around.....love the hemi.....21 mpg when not towing which is astounding with a 385hp V8.

[floyd]

What transmission is being used, by code or number?

[thrifty bill]

I typically use the tow haul mode on my F150, but.... whenever I shut off the truck (think every rest stop, gas stop, or whatever), when I restart, I am no longer in tow/haul mode. I get reminded on steep declines, where I have to use the brake quite a bit to control/reduce speed.

So I find tow haul mode useful on grades, particularly downhill. YMMV.

I do love it when the RV guy thinks he knows more than the truck's manufacturer. When in doubt, I go with the TV manufacturer's engineers over an RV service tech.

[Raspy]

Trying to decide who has the most credibility when telling you to engage or not engage tow-haul, misses the point completely. And deciding the computer is smarter than the driver, so leave it in charge, also misses the point.

Now, imaging yourself driving a tow vehicle with a standard transmission.

When not towing, and driving around town, you use lower RPM and shift earlier. Acceleration is more gradual, the engine is running slower, at speeds where it produces less power.

Now hook up to a trailer and begin towing in the mountains. Higher RPM is needed, lower gears are used, engine braking becomes much more important. The full horsepower of the engine is required, economy is less important than cresting the next hill, or keeping up with traffic.

The automatic transmission programming is designed to match the transmission to the job being performed by the tow vehicle, and do it with the greatest efficiency and practicality. Sometimes more power is needed and sometimes more calm driveability is needed. But it can never predict upcoming hills or downgrades. It needs to not only shift the trans, but protect it against overheating, and manage the engine's horsepower, as needed.

Modern transmissions learn about your driving style and develop a program that best suits what you are doing. Then, you can signal it that you are about to work it harder and need more performance. These are the two modes. Normal and Tow-Haul. Neither one is absolute. You can use tow-Haul in the city while not towing, or in the mountains to get the most out of the engine braking, etc.

The decision is up to the driver. Try to minimize excessive shifting, try to keep the engine in its power band, and where the throttle responds well. Try to get good engine braking on downgrades.

Pay no attention to empty recommendations like "never" tow without tow-haul, or "trust the computer" to do the right thing. The automatic transmission is simply a gearbox controlled by a little helper. But it is never perfect. Placing different demands on the vehicle requires a modified driving style to get the best performance. We have a convenient switch to notify the "little helper", that we either intend to drive easily, or work the truck harder. Normal, or Tow-Haul. That's all there is to it. Let the "little helper" best apply the engine and transmission to the job at hand.

Modern transmission programming will also not allow the transmission to hurt itself.

Finally, you can even override these two modes by locking out overdrive, or any of the higher gears. This limits upshifting while coasting and then downshifting on the next grade. Or eliminates hunting between gears on steady grades. It allows good engine braking and increases cooling.

The best policy is to use the available tools to best match the engine and transmission to the job at hand, and not just follow someone else's rule about do or don't use tow-haul.