Stupid trailering question - 2016 TLC

[JohnPW]

I recently purchased a used 2016 LC, and am trying to figure out the transmission settings for trailering a boat & trailer (total weight @ 3500 - 4000 lbs?). The manual says to operate in S instead of D...but there's also the "ECT PWR" button, that some have compared to the "tow/haul" setting I'm familiar with on the Sequoia and my previous Tahoe. Questions:

1.) best practice to tow in S? It really seems to allow much higher revs, much bigger change to settings than the S mode in my Lexus sedan. This should be good for towing I imagine, but may hit mpg pretty hard.

2.) manual says set S at for4, or up to 6, when towing. Given my weight range, any advice on what max gear to set on the interstate?

3.) how does the ECT PWR button fit in? Does it do anything when you're already in S? The 8 speed seems to shift much better with ECT PWR on for ordinary city driving...seems both S and ECT PWR are tweaking shift points....I'm assuming it doesn't change anything when S, correct? Very limited explanation in the manual.

4.) any other advice when trailering a 21 foot boat with this vehicle?

Thanks

 

[tirewater]

The manual wants you to stay in a gear range that allows the torque converter to lock up. I don't know much about 8 speed auto, but I imagine that speeds 7 & 8 probably don't lock up the torque converter. Torque converter slippage generates a lot of heat, so keeping it 'locked' keeps the transmission cooler regardless the RPM of the engine.

You can buy a cheap OBD reader + phone app to keep an eye on transmission temps if you want. Although that tends to make us more OCD...

 

[Sandroad]

I drag a camper trailer all over the country that's about the same weight. I suggest using S6 and the ECT PWR mode. The higher revs don't hit gas mileage much. It's the amount of work the engine has to do, not the engine rpm, that has the most effect on mpg. Let the beast spin a bit and both it and the transmission will be happier. There's an excellent thread (actually several) on towing, so check with those threads for towing advice too.

Edit; found it for you.....

Towing with a 200-series Toyota Land Cruiser

 

[TeCKis300]

I recently purchased a used 2016 LC, and am trying to figure out the transmission settings for trailering a boat & trailer (total weight @ 3500 - 4000 lbs?). The manual says to operate in S instead of D...but there's also the "ECT PWR" button, that some have compared to the "tow/haul" setting I'm familiar with on the Sequoia and my previous Tahoe. Questions:

1.) best practice to tow in S? It really seems to allow much higher revs, much bigger change to settings than the S mode in my Lexus sedan. This should be good for towing I imagine, but may hit mpg pretty hard.

2.) manual says set S at for4, or up to 6, when towing. Given my weight range, any advice on what max gear to set on the interstate?

3.) how does the ECT PWR button fit in? Does it do anything when you're already in S? The 8 speed seems to shift much better with ECT PWR on for ordinary city driving...seems both S and ECT PWR are tweaking shift points....I'm assuming it doesn't change anything when S, correct? Very limited explanation in the manual.

4.) any other advice when trailering a 21 foot boat with this vehicle?

Thanks

1) Best practice is indeed to put it in S mode. The S function is to limit the highest gear that the transmission will try to use. The vehicle is smart enough that it likely will come up with the right gear to get the torque converter to lock. But it's much better to just tell it so it doesn't hunt. Shifting/hunting heats up the transmission, as every time it unlocks the torque converter to shift, extra heat is generated in the torque converter and internal sprag/clutch packs in the transmission. Potentially leading to more wear.

2) I have the 6-speed and manual recommends S4 (3.909 overall ratio). S6 in the 8-speed is almost equivalent but lower (3.307). S4 tows my Airstream very well and I seldom seek S5 unless I have a tailwind downhill. I'd say my setup is heavier in load due to weight of trailer, more frontal area, and 33" tires. I think S6 should be a great all around ratio for you. Depending on how aerodynamic your trailer/boat is, you may very well be able to use S7.

3) The S function largely only concerns itself with limiting the highest gear. It's a semi-manual shift mode. ECT is where most of the alternate engine and transmission mapping magic happens. Copied from another thread:

... I use ECT all the time while towing. It's fairly pronounced on the 200-series as even my wife notices it when she drives after I forget turn it off after a camping trip...and she usually doesn't notice anything.

As a tuner, I can tell you it does at least the following:
1) Revised throttle pedal maps. These are more aggressive such that initial pedal tip in dials to more aggressive throttle maps
2) Revised transmission shift maps. The transmission is more aggressive in holding gears and to higher rpms.
3) Likely changes to engine maps and VVTi controls (cam angles) to keep the motor more on "boil".
4) More engine output = loss of mpg!

4) Nope, other than we'd like to see a pic!

 

[GordJ]

The manual suggests a lower gear because of overheating on long downhills, as I interpreted it. As nearly as I can tell, coasting on long downhills has the possibility of an idling motor not turning over fast enough to circulate coolant. I’ve got over 10,000 miles of 200 towing a (?) 4,000 lb.+ travel trailer and a couple thou. more with my 3,500 lb boat and I haul in D on the standard susp. setting in the LX and normal, not Power, tranny setting. I have never had any reason to go to Power or a lower gear. The last time I got home with the LC after 5,200 miles I had 200,000 miles on the od without gearing down or punching the power button.

 

[Dan Higgins]

I can echo pretty much what others have said. I've done a fair bit of towing now with my MY16. Not sure which manual you are using but the manual for my 2016 specifically recommends S6 and no cruise control.

Yes, use ECT. ECT essentially keeps the transmission in a lower gear longer before upshifting. Again, the point is to avoid overworking the tranny/engine by "lugging down". This is true in S-mode. Remember, S-mode is not manual shifting. (I know, its confusing.) Rather, S-Mode is automatic mode that gives you the ability to limit how high the transmission will shift. Setting it to S6 limits the automatic transmission to gears 1-6 thus avoiding the "overdrive" gears - 7 and 8. 7 and 8 are better for gas mileage when your not accelerating or ascending or whatever.

I find with my 6,000# travel trailer that I can cruise on flat roads at 65mph in S6 and the RPM sits a bit above 3,000. Maybe not the best for gas mileage but in the sweet spot for torque.

Oh, and being in S-mode lets you easily lower the limit ("down shift") when you want to using engine braking to control descent.

 

[JohnPW]

Thanks for the reply’s. I’ll keep it on S6 with ECT PWR on when towing.

I’m still confused around S vs ECT PWR...I know S will limit the top gears but it also seems like a lot more is going on in terms of shift points in lower gears while in S. The truck revs much higher and shifts later in S vs D (similar to, but more pronounced than the S mode in my Lexus sedan). ECT PWR seems to do something similar (while not limiting top gears like S)...but the difference in shift points is more dramatic S vs D, than it is in D while switching on ECT PWR. Am I making any sense?

I notice a meaningful difference in shifts in D when I turn ECT PWR on. I notice a bigger difference in shifts when i go from D to S6, at lower speeds where I’m below 6th gear anyway. I don’t notice any change from turning on ECT PWR when I’m already in S6. Based on advice here I’ll use both when towing, but I’m not convinced that ECT PWR is changing anything when in S mode. Any thoughts?

 

[Sandroad]

Interesting observations. I’ve used ECT PWR all the time to improve (IMHO) shifting of the 8 speed ever since I bought the LC. I’m not sure I’ve noticed the changes you’ve noted when using S6 while I’m towing. But, I’ve also never used S6 while not latched onto my camper, and of course the extra stress of hauling that around changes powertrain activities a lot. I’ll have to do some experimenting with S mode while running free. Who knows, maybe I’ll end up with a 7 speed tranny.

 

[TeCKis300]

The 8-speed may very well be calibrated differently. S is semi-manual mode. But it's also S for sport. So it may be very possible that it's holding gears longer.

The most notable difference to me when using ECT power is the throttle peddle map changes to have more aggressive tip in. When using ECT power without towing, I find that the pedal is touchy, and will jump off the line with minimal input. That's what my wife notices too when I don't switch it back out of ECT PWR after a weekend towing. The throttle mapping difference is there both in D and S.

 

[linuxgod]

Thanks for the reply’s. I’ll keep it on S6 with ECT PWR on when towing.

I’m still confused around S vs ECT PWR...I know S will limit the top gears but it also seems like a lot more is going on in terms of shift points in lower gears while in S. The truck revs much higher and shifts later in S vs D (similar to, but more pronounced than the S mode in my Lexus sedan). ECT PWR seems to do something similar (while not limiting top gears like S)...but the difference in shift points is more dramatic S vs D, than it is in D while switching on ECT PWR. Am I making any sense?

I notice a meaningful difference in shifts in D when I turn ECT PWR on. I notice a bigger difference in shifts when i go from D to S6, at lower speeds where I’m below 6th gear anyway. I don’t notice any change from turning on ECT PWR when I’m already in S6. Based on advice here I’ll use both when towing, but I’m not convinced that ECT PWR is changing anything when in S mode. Any thoughts?

I have a '13 with just 6 gears, but on mine ECT PWR definitely changes the throttle map so that off-the-line throttle is more responsive (jerky, as my wife says). It also changes the shift points to be more aggressive, especially the downshift when you pass, if you're not flooring it. If you pass by stuffing the pedal to the floor then ECT PWR probably does nothing since that triggers the transmission to shift into the lowest gear possible anyway.

 

[TeCKis300]

The manual suggests a lower gear because of overheating on long downhills, as I interpreted it. As nearly as I can tell, coasting on long downhills has the possibility of an idling motor not turning over fast enough to circulate coolant.

Would like to clarify that this is not likely the concern. When going downhill, there's no combustion heat. The injectors are fully shutoff under coast and engine braking. The heat generated from engine braking is mostly translated into the air that's being compressed and pumped through the engine.

 

[chilibit]

I suspect the overheating was actually related to brakes not engine. I use a P3 controller and I am not aware that engine braking actuates trailer axle braking.

 

[TeCKis300]

^Well, yes, that's a general concern. But Gordj was talking about circulating coolant in the engine.

 

[linuxgod]

You definitely want to stay in gear downhill. I tried Neutral on a long downhill in CO over the summer with travel trailer in tow and despite the engine sitting at idle and the drivetrain spinning freely the transmission temp was higher than staying in 4th gear. Also the truck kept speeding up and I had to ride the brakes to keep it under 75.

Note: Normally I do not use neutral on a downhill and would properly engine brake in 3rd to slow my speed but I was curious. I also noticed that 5th or 6th gear at 60mph seems to get nearly the same MPG as 4th gear (within 0.5mpg) when pulling my trailer. So use 4th (or 6th if you have an 8 speed transmission).

 

[GordJ]

^Well, yes, that's a general concern. But Gordj was talking about circulating coolant in the engine.

My recollection was incorrect. It was the charging system that needs revs.

Okay, the LX manual for the 6 speed says

"to maintain engine braking and charging system performance when using engine braking, do not put the transmission in "D".
If in the "S" mode, the transmission shift range position must be in 5 or lower. "


This is the only statement I can find in the Owners Manual for a '14 LX. It doesn't mention recommending "S" or "Power" or any other settings. All it says is if you are using engine braking you should gear down.
And I would never ride with someone who thought neutral was an acceptable setting on a downhill. That is inherently dangerous.