Starting in S Mode

Manual says S5 or lower. I found that I can only tow my rig in S5 going downhill or with a tail wind. Consequently most of my towing is in S4 with ECT on.

 

I really just wanted to sneak in a Lt Dangle jab there. I'll take you at your word

 

Maybe I'm totally wrong but towing hard in S5 (or any overdrive gear) just seems like bad practice. The TC will be unlocked and the extra heat from the impeller/turbine spinning could eventually cause a problem or at the least premature degradation of transmission fluid

 

The thing to keep in mind is the truck only goes in 5th when it's easy. Otherwise it's 4th, or in my truck with 33s, lower.

Ultimately do what you're comfortable with.

 

Can’t tow hard in S5 unless you have gear lock. In my case S5 with a heavier than normal load won’t hold under any throttle pressure to maintain or increase speed and will eventually downshift to 4. I’ve tried S5, towing, but it dosen’t work for me unless I have a good tail wind or going downhill. And out here, downhill is hard to find.

 

Man, hard disagree here. ECT eliminates nusiance shifts a ton. Also cruise and towing is a no-go in my book.

 

You need to stop handing out actual real information.

I mean, come on man you're telling these people to use S4 when towing! That could cost them an extra $30 or $40 on that trip. The smart people will leave it in D, and save gas money.

How much to rebuild an Aisin AC60F?

 

I found ECT totally unnecessary for anything towing much under 2k lbs. It just wastes fuel. S5 is all thats needed. Kind of a crap shoot towing my boat in ECT, or just leaving it in S4-S5.

 

What if you never get those so called nuisance shifts? ECT just make the engine louder, transmission will have longer shifts, and waste more fuel when i use it. Seems the stuff i tow S5 is plenty.

 

I guess it would depend on what you are towing. Dude hauling a riding lawn mower on a small utility trailer? Truck isn't even going to know it is there. Tow something with some wind resistance, or weight up a hill? Different situation.

 

I have, my boston whaler boat...its at least 2k lbs with the trailer. I've used ECT, but starting to think its now overkill. I'll bet S5 will be fine....S4 for any bigger hills. I agree i can pull a lawn tractor loaded in my utility trailer using D if i choose when on flat roads, but S5 works well the rest of the time.

 

The manual doesn’t actually say to not use 6th gear when towing or at least Ive never seen that in the manual. It says to not use 6th gear when engine braking, which seems like kind of a no-brainer since 6th isn’t going to slow the truck down much.

Out of curiosity, I did some googling on the subject today and I could not find any conclusive reason for not letting the transmission do its job and use 6th when it feels like it. In this day and age of electronically controlled transmissions, why would engineers design a transmission that implodes when towing in D?

My guess is that there have been transmissions manufactured in the past (or maybe even still today) where the manufacturer recommended not using the highest gear (often called overdrive) when towing and that recommendation has been passed down from father to son over the ages.

 

"● Vehicles with an automatic transmission: To maintain engine braking efficiency and charging system performance when using engine braking, do not use the transmission in D. If in the S mode, the transmission shift range position must be in 5 or lower."- from my 2017 manual

Eh, I can see your argument, but since it follows after the period, I consider it to be a separate thought. My interpretation is just my own.

Toyota could be clearer on this though.

 

Both 5th and 6th gears are overdrive, as stated earlier, 4th is 1:1, the first non overdrive gear in the auto box. Unless towing a light load, using an overdrive gear will have the converter going back and forth from locked to unlocked, it's going into an unlocked situation because it can't hold the load, and has unlocked to get the extra couple of hundred revs, but slipping, shearing the fluid, heating it drastically.

 

Boats are kind of their own thing towing. All I knows is if I pull my SxS with it's roof and windshield on just S mode, I can tell immediately that ECT is not on. It collects so much wind and slows the truck down noticeably. My cargo trailer is a V nose and does the same.

 

I just don't experience this. I know what "should" happen, but in the real world my temps only vary by a few degrees unless I am climbing and dropping gears. I am monitoring my converter via OBD Fusion, along with the temps.

 

Did your research happen to cover torque converters like I mentioned earlier? Overdrive isn't just the highest gear, it's any drive gear that's less than 1:1, and the Tacoma has two. 5th gear is .69 and 6th is .58.

 

Hard disagree on what? My rig? My 2k miles in the mountains? My experience with both?

As stated, I ran S4 at 65-70 mph, and the only time the truck shifted was on grades causing the 4-3-4 shifting. I began to anticipate this and simply shut off the cruise control. Other than that, cruise in S4 worked better than fine. ECT didn’t do anything significant in my experience.

 

It says exactly the same thing for the manual transmission which further implies that it has nothing to do with a torque converter over heating.

 

I could not find any authoritative evidence online that there is something special about the torque converter lockup when in 5th and 6th gears. Do you happen to have a reference?