Tow Haul Is Stoopid!

For towing any ways....What does it do? Change the shift curve and allow OD when no load....?

I forgot to engage Tow Haul taking my 25 foot RV out of Kingman for ~30 miles... BUT...

I shift anyways...had it in 4th most of the way.

The fact it allows OD is odd as that's the first rule of towing: NO OD!

I do use it but find it less than ideal as it's easy to forget. One needs to pay attention to the engine and be shifting anyways... I wish they'd have a no OD option...I never made mistakes like this when towing withe my 4Runner of Tacoma....

Still not even sure if you're supposed to put it in D and TH and go or leave it in 4th.... I've been D and TH with no issues.....But still see a graphic image of a handful of gears from some guy towing in OD!

Greg!

 

Tow/haul button alone is not end all for towing. You’re supposed to use it in conjunction with S (sequential) mode to manually prevent the trans from going into 6th and 5th if you don’t need to.

 

What??

Yes, Tow haul is for towing.

Works as advertised and you don’t necessarily need to shift the trans.

 

The Tow/Haul button is for towing & hauling?

Oops...I have only used it when the light turns green to get a superficial, short-lived adrenaline rush while draining my gas tank.
My bad.... Anyone else?

 

Me too. I never tow anything as I haven’t bought a boat yet. I push the button when I want a little more giddy up in town. Makes a big difference in throttle response.

 

The owners manual states you should put the transmission in S4... below is from my 2019 OM under the “Trailer Towing Tips” section:

 

Mine doesn’t have tow haul. I just leave it in S4 or S5.

 

Greg -- I like that tow/haul does not limit the transmission from shifting into overdrive gears. The alternative, that you seem to prefer, is that T/H would automatically limit the maximum to 4th gear. I much prefer the choice Toyota made that allows me to make that decision myself (maybe I want to use T/H when I'm not towing). Are you saying you want less control over the truck systems and prefer default modes that take away your choices?

 

I wonder.....

Since it violates the rule of not towing in OD....how smart is it? I much prefer shifting when I feel I should and that saved me today

Well....

Being an old timer ANY shift to OD is scary. I notice it can linger in OD as it can't predict terrain so there is a lag. When I see a up grade I judge as steep I drop into 4th. When same as down grade I'l grab 3rd or even second.

TH is clueless as to my actual load so doesn't respond properly IMO. I'm hauling ~8000lbs.....

A couple of time yesterday climbing up I-40 towards Flagstaff I was clearly climbing. I let TH do its thing then dropped into 4th and sure enough I was going up hill, ~5% grade or more, in 5th or maybe 6th.....

Should I ever be in OD hauling 8000lbs? Does having TH engaged make any difference towing in 5th or 6th?

I also think I read here sometime ago that shifting out of D effectively turns off TH.

I wish I could solid firm answers with data and Toyota tech to back it up.... As posted above the manual isn't written all that well regarding this...

Thanks!

Greg

 

I think S mode turns off tow/haul from working

 

Haven't some reported that they get better MPG in tow mode, when not towing anything?

 

No, it does not.

 

I run in OD all the time when towing. Someone explain why this is such a sin. I have seen zero evidence, from others or personal experience, to indicate there's an issue using the full range of gears.

 

As @ColoradoTJ mentioned,
Your comment is not a bullet point, it's a subsection or addition to of the bullet point above it.

 

Certain trucks don’t recommend it. Our transmissions are strong enough that we can tow in OD

 

Sounds like you want a super smart system - which the Tow/Haul isn't. It can't predict terrain or amount being towed, it just goes by engine load. Anything I've read towing in 5th and 6th is just fine, you just don't want the transmission to be shifting often - which is what tow/haul does. On flat lands when cruising I don't even engage tow/haul since it'll hold lower gears than is I like - if it ever starts hunting I'll click it on to stop that. I would say any hills just flick it into S mode and downshift yourself, then go all the back up to S6 on flats and let the truck do its thing.

 

I am no towing expert but monitoring trans temps on my scan gauge I run cooler in S4. Even on relatively flat ground if I shift it up to S5 I almost immediately show trans temps climb. So personally that's why I wouldn't want to tow in D.. From my experience S4 with tow haul seems to keep my truck the happiest. T/H definitely makes it more responsive especially off the line towing an holds gears longer.

 

I'll take a stab at this Greg.

Always use S4 when towing.

You can also push the Tow/Haul button. Or not. Your choice.

 

I am in total agreement with you on this. There is much debate on this forum (ex: if the torque converter locks up or not when in "S") in addition to the current discussion, but no Toyota source (that I'm aware of) to get straight answers to these questions. Seems like a big miss to me, but like so many things sold today that seem to 'dumb down' how they speak to customers.

 

There are a lot of variables that the mfg (Toyota) cannot give 1 generic answer to be the correct answer to every case regarding towing. They can give guidelines, but that's about it. What is applicable for one person towing 1k lbs in 120F amb temp close to sea level will not be applicable to someone towing 6500lbs, 60F amb temp at 4500ft elevation.

The TCC is something you personally should be able to notice or feel. Very noticable IMO. The gear will remain but there will be a slight decrease in RPM when it closes or slight increase when it opens (typically 200-300 RPM).

 

Let’s not overthink this people. Get an app that lets you monitor whether the torque converter is locked or not. Use tow/haul when towing and do whatever you have to to keep the torque converter locked. Towing with the torque converter unlocked is what generates heat and wear.

 

My earlier comment was referring to not having a Toyota source for reliable answers as to how a mechanical or electrical system is designed to operate. I was not looking for guidelines on how to operate the truck in various situations, which naturally vary by situation and by how the system is designed by Toyota to work.

My comment about the debates we have on this forum on technical issues (in this example about the torque converter lockup) was to illustrate that there seems to be confusion about its operation, which leads to discussion on this list. I appreciate your taking the time to reply, but I am not confused about when the TC goes into or out of lockup.

 

This.

Late 80s and 90s trucks were known for burning up overdrive.

 

It must be the S/C that makes TH seem like it is doing what it’s supposed to do. I put it in TH when pulling my boat (#6500) or other heavy loads and it eases along at 75...no gear hunting, no “S4”, I leave it in “D” unless going down a grade and then I use the trans to save the brakes.

 

T/H is noticeable from a take off. It holds 1-2 and 2-3 shift longer which is a massive help when pulling a big load. Our trucks have so much torque that they normally shift asap for fuel economy

 

+1, driving a Toyota not an old Ford. The only thing tow/haul did on my older Fords was lock out of OD. I can do that manually on the Tundra. Tow/haul increases throtlle response and enhances engine braking when decelerating.

 

I have the OBD Fusion app and when in S mode the TC is not always locked. It behaves much like D mode in that as you are Warming up, accelerating, or going up a grade that puts a load requiring TC unlock it does so. Once in a higher gear and relatively stable load it locks.

Just passing on my observation from OBD Fusion.

Is anyone seeing it stay locked in S?