When do you use tow/haul mode?

As the title says, when do you use tow/haul mode?

Do you use it any time you have a trailer hooked up, or only when its past a certain weight? I've noticed some people here say they use tow/haul for things like moving their ATV around which I find strange.

Is there anything wrong with not using tow/haul when pulling small/moderate loads (1000-2000Lbs) and taking it easy?

 

Do you want peoples opinion or what Toyota wrote in the manual?

 

Just bought my Tundra 4x4 a few days ago, was reading the manual last night, and don't remember everything it said on this topic.

My take-away was:
It will shift differently when Tow/Haul is on, which means it's designed to manage heavy loads. Therefore, the vehicle will need more fuel in Tow/Haul mode.
Engine braking also comes into play: In manual Shift mode, S-2 will apply more aggressive engine braking than S-3, etc.

As I read (and re-read) about VSC and traction control (TC) it also became apparent, even in 2WD mode these systems will engage the front wheels to manage traction/slippage.
Auto-LSD appears to turn VSC and TC off. Without being direct, the manual cautions against operating with Auto-LSD on all the time - possibly for this reason.

Since my Tundra 4x4 has optional trailer brake wiring, when I haul my 21' Jayco I'd be comfortable not using any of these systems / tricks.

If I ever tow a heavy trailer with non-functional electric brakes, I'd employ both Tow/Haul and S-3 Shift. Might also add Auto-LSD (VSC Off), in which case it'll be in "True 2WD Mode."

 

I press it every time I need the engine to reach the red line as soon as possible.

 

I use mine pulling my 21' Jayco but I have also forgotten to use the tow haul mode and didn't notice any trouble pulling it.

 

Turning VSC off while towing down the highway sounds like a really bad idea. I’ve driven my truck 94k miles and haven’t found a use for the Auto LSD yet.

 

Just refreshed about Auto-LSD: The manual recommends not using it while driving normally. It's for when you're stuck in bad conditions (snow / sand) and should not be engaged 'while the wheel is slipping,' ie: engage it without your foot on the gas.
It functions by applying brake to the slipping wheel, which leaves me thinking: The rear differential does not have LSD in the traditional sense: Makes me want to engage Auto-LSD, then jack it up and see which way the other wheel spins when I spin the one I'm looking at.

VSC Off might 'sound like a bad idea.' But, I'm considering it's summer time with dry roads and idyllic weather when the need for VSC would be minimal.

 

A-TRAC ("Auto-LSD") is on by default. Pressing traction button once makes it slightly less aggressive. To make it even less aggressive you need to press and hold it for 3 seconds. Then you can go throw some rocks, mud and snow like you may see in youtube videos.

But that has no relation to towing.

Tow/Haul button reprograms engine computer to react more to accelerator pedal, as well as transmission computer to switch gears less, since doing so with something heavy on truck's tail will wear friction plates more quickly.

 

It’s definitely an open diff - the wheel would spin the opposite direction.

As for the VSC, if you don’t need it because conditions are great - it’ll never come on even though it’s active. All you’re doing turning it off is potentially robbing the computer the ability to save your ass in a loss of control scenario. The only purpose I’ve found to turn off VSC is in slush/deep mud or doing a burnout/donut when you don’t want the computer to cut power based on wheel slip/spin.

 

I only use my tow/haul when I feel I need it. I would say if the trailer is over 3000lbs I would likely use it. If under I would not. When pulling my horse trailer through towns I usually turn it off because its jumpy from a stop. Have to control the right foot too much or the horses get an uncomfortable ride.

 

I run in tow /haul ass mode all the time, even if not towing, it makes the throttle response more aggressive, and holds the trans in a lower gear longer, more fun to drive.

 

Lotta opinions and not so correct(?) info in this thread.

Our 2nd gen Tundra 4x4s mosy certainly do not engage the front wheels at any time while the truck is in 2wd. This ain't no fancy schmancy AWD system.

I also do not believe it is possible to fully defeat the TC and VSC (except possibly in 4lo, but don't quote me on that), even by entering the truck into what some refer to as "beast mode" (holding the trac button down 3sec (2x) after selecting auto LSD in Neutral).

Do you guys not find open locations with limited traction at which to "hoon" your trucks a bit, if not only to know how your truck will respond in these situations and what the different settings actually achieve?

I personally drive in Auto LSD as much as possible around town. It will allow you SOME wheel slippage while not killing engine power, which can be very helpful for quick acceleration without abruptly stopping your progress in the middle of an intersection. I have played around a decent bit in "beast mode" and the nannies will still intervene at a point, the system just allows a lot more shenanigans before shutting down the party.

I kinda feel like Toyota did a pretty good job providing a range of safety nanny intervention available to drivers of different comfort levels. If you feel safest with the nannies on full guard, more power to ya!

 

...But this was really about tow/haul mode.

If I am pulling a trailer, it's typically our 26' travel trailer at about 6000lbs or one of the boats (under 5k) to and from the boatramp.

I do not use tow/haul at the lake. But that's probably because I have had several beers and am not thinking about it.

Pulling the camper, I definitely use tow/haul every time. Since most of our driving is fairly mountainous, I'm almost always in S4 or S5, manual shifting to reduce shifting on changing grades and twisty roads.

I would suggest if the truck is not hunting gears all the time with your lighter loads, maybe you don't require the assistance of the tow/haul mode. If their is too much shifting for your likes, use tow/haul or manual shift.

 

After disabling VSC (3 seconds trac button press) in 4HI I didn't notice any intervention. The terrain was a sandwich on log roads comprised of ice, 4-8" of dry fluffy snow and 3-4" of hard packed crust. It holds 200 lbs of me, but not the truck. If you stop you can't start moving again because of very little traction on ice and obstruction the crust creates. VSC off and it can go anywhere. Only watch in horror how quickly the fuel gauge moves to zero (MPG is 1 to 3)...

Before VSC off I was either using winch or, more often, simply giving up.

 

I would also advise boosting up slippage additives with something like Lubegard HFM in order to minimize frictions wearing out. Gears you can somewhat control, but torque converter lock up - not. HFM does a great job protecting clutch packs.

 

I agree that there is little to no intrusion in 4hi and seemingly zero intervention in 4lo. Had to pull out a friend last year (up the snow covered hill) and definitely didn't even find dirt.

These trucks are pretty badass in the snow.

 

I shall have to engage in some reading.

Thank you

 

HFM says 1 oz per 1 qt, but don't add that much. HFM is for converting old style ATF into new style, for transmissions with controlled limited slippage, like ours is. Since WS is already the right ATF, only a small amount of HFM is needed to replenish and boost factory additives. I do just 1-2 oz in 6 qt drain&fill. Have HFM in all my vehicles for years with no downsides. Old ATF comes out much cleaner, which positively indicates a lower frictions wear.

 

That's the reason for winter being my favorite camping season!

 

I use tow/haul mostly when pulling my 29’ travel trailer. It’s usually flat highways miles.

 

My truck bed is loaded and my pop up trailer is a little more than 2000 lbs, and only use tow Haul mode when going up thru the mountain pass over 5000 ft on the interstate. I’ve never seen my engine temperature gauge needle move.

 

I used mine the other day to blow away a 2019 Ram that challenged me at the traffic lights.

 

Thanks all. I read and 'liked' every post after my last.

A complete rookie to operation of these new fangled 'nanny' buttons and want to know what is their job and how they cooperate. Perhaps I've opened too many cans of worms at once.

OK: Tundra's do NOT have an LSD differential. Confirmed by reading the factory Tundra sales brochure at 'Braking' and visual inspection of the differential: It has a green dot. The 'Auto-LSD' button is misleading.

The features are all interrelated and I need to understand because I'm a member of the PCDA (https://pcdorymen.com/): After a long day fishing, the last thing you want is to be stuck in soft sand with a ton of boat/trailer/gear/fish behind you and LSD / 4WD that won't engage, or an Auto-LSD / VSC system slowing progress. The goal: Get to about 35-40 MPH asap, because the fluff will rob speed until you're stuck.

I'll keep reading about 'beast mode' and will look again at top speed in 4-Low, S-2 or S-3.

A 2001 4Runner was my newest ride to date and I have a 1996 Suburban. Those 'beach rigs' work fairly well although we all want more power!

Now that I have it, 4-High, Auto-LSD / VSC Off + Tow/Haul on, is exactly the mode I want, not that I want to abuse this dope Tundra 4x4! When I hit pavement, turn LSD / VSC back on but, perhaps leave it in Tow/Haul mode until I reach open highway. Then, try to get MPG above 2-3.

 

Hmmm, "...don’t want the computer to cut power based on wheel slip/spin." VSC Off ... Check!

 

Auto-LSD only works in 2WD.

 

True. But the truck will do the same (brake activated trick on all four wheels to attempt limiting slippage in 4wd...

The following is a nice thread which goes into detail about what is working, how, in each of the modes etc.:

https://www.tundras.com/threads/your-2nd-gen-controls-and-how-they-work.627/

Hope it is helpful to others!

 

Thanks I'll take a look. Only ever read that it works in 2WD and using the 4WD switch will disable it.

 

Reading the post again, seems like toyota calls it "A TRAC" when in 4wd and "auto LSD" in 2wd. Same ABS based system to limit wheel spin.

Honestly, I can hardly remember the ins and outs of it all and have to experiment to achieve the desired result from time to time.

I DO recall the truck shutting me down in "beast mode", so I don't think the nannies can be truly turned OFF. (Edit) I do believe this was in 2wd tho

 

Will also read '2nd Gen Controls and How They Work.'

Regarding this thread topic: When do you use Tow/Haul Mode?

This morning, I learned that I will NOT use it again in a situation I'm confronted with every day on the way to work:

1) There's a 2 lane highway (55 MPH) with my merge lane entering on the left (a short 3rd lane entrance ramp)
2) You come under the bridge (the opposite direction of highway), then
3) Bank sharp left and step on the gas, while looking over your right shoulder for a merge opportunity
4) It's so tricky, I instinctively assure my right side-view mirror is not fogged up every morning: I've seen more than one car upside down in the median.

This morning, I did this (in 2WD) with Tow/Haul mode on while the roads were very wet from deluge last night.

Auto-LSD effected correction as the left-rear broke loose upon up-shifting sufficient that the anti-slip warning lit and beeped three times, all at the moment an 18 wheeler was passing to my right and throwing up spray. There's plenty of HP/Torque available, apparently. I was not flooring-it. The event was shy of frightening, possibly due to corrections Auto-LSD/VSC effected. But Tow/Haul mode is too aggressive for this situation and I'll save Tow/Haul for better road conditions, hauling up hill and/or dory boat recovery operations. I'm looking forward to the latter, more and more.

 

When I am either towing or when I need to haul “butt”.

My kids call it ludicrous speed mode.