Towing with the 8 speed transmission question (1 Viewer)

[vegasfj40]

Hello everyone. Those of you that tow a small trailer with your cruiser, what gear do you leave it in? Do you just leave it in Drive or do you put the transmission in manual mode and select a gear? I kept the transmission in 6th gear and that seemed to be fine running 60 to 65 on the highway.

 

[vegasfj40]

I noticed in the owners manual that it suggests not towing in Drive and to keep it in S mode and 6th gear. So I will just keep doing that.

 

[Hants]

I’ve been towing in drive and carefully monitor transmission gear and temps (via odbii scanner). Have ECT on all the time. Only use S when hunting gears or long downhill grades.

rarely have it sit unlocked torque converter very long. But I do watch... if you don’t have a monitor, S6 is a safe plan. S5 or lower if you need.

 

[tdcruiser406080100]

Hello everyone. Those of you that tow a small trailer with your cruiser, what gear do you leave it in? Do you just leave it in Drive or do you put the transmission in manual mode and select a gear? I kept the transmission in 6th gear and that seemed to be fine running 60 to 65 on the highway.

View attachment 2600550

I’ve towed quite a bit with my 2020HE and a travel trailer about 6;800lbs. I do use the manual mode where you can set the upper gear at 5, 6, 7.. whatever.. I like to be around 3;000 rpm towing that kind of weight. You may be able to be a bit lower RPM with your trailer. I use cruise control at times but I actively downshift for engine braking. (not waiting for cruise control to do it). Overall been a great tow cruiser..

 

[Dan Higgins]

I have been towing our 6,000# travel trailer throughout the mountain West for 4 years. I follow the instructions in the Owners Manual. S-mode, no higher than S6 (no overdrive), ECT PWR. Being in S-mode also allows me to help control the speed on descents w/o excessive brake use on long, steep mountain passes.

 

[Tex68w]

Hello everyone. Those of you that tow a small trailer with your cruiser, what gear do you leave it in? Do you just leave it in Drive or do you put the transmission in manual mode and select a gear? I kept the transmission in 6th gear and that seemed to be fine running 60 to 65 on the highway.

View attachment 2600550

Love the Casita!

 

[CharlieS]

I guess small is somewhat relative. We have a NoBo 10.6 that has a UVW of 1,990 lbs. I just run in Drive and can hardly tell it is there.

That was the day we picked it up, with my old '13 200, before I had figured out the hitch height properly. I now have a '16 with the 8 speed.

 

[vegasfj40]

I guess small is somewhat relative. We have a NoBo 10.6 that has a UVW of 1,990 lbs. I just run in Drive and can hardly tell it is there.

View attachment 2600814That was the day we picked it up, with my old '13 200, before I had figured out the hitch height properly. I now have a '16 with the 8 speed.

My Casita weighs about 2500 lbs so not much more than what you have. I will probably just keep it in S6 and run it. Not sure if the transmission would hunt a lot between 6 7 and 8 if kept in Drive.

 

[Sandroad]

6th gear all day long. It lets the engine breathe well, keeps the torque converter locked up, gives better engine braking, and is simply a more responsive and happier towing experience.

 

[linuxgod]

@Hants what temps do you see in both the A/T temp sensors if you're in D?

I'm +1 with @Sandroad. 6th gear on the 8 speed, 4th gear on the 6 speed. Those are the 1:1 gears - anything above is an overdrive. (IIRC the manual in the 2008-2015 says you can run in 5th... not sure if they say 7th is OK for the 2016+ though). The manual says not to use your highest gear(s) when towing.

Of course you may be able to run in a higher gear. The weight and aero of your trailer matters, as does tire size, vehicle aero, and general vehicle load, of course. If you have stock height, stock aero, stock tires, and are pulling a small boat or open trailer with dirt bikes you can probably run in your OD gears. If you have a 2-3 ton box trailer and are on 33s then you should use your 1:1 for sure.

I've done a LOT of OBD2 monitoring in the 20k+ of towing I've done with the LC. My experience is with the 2008-2015, but I can see no reason it would be any different with the 8 speed:

• Heat is your enemy on transmission life. Do everything you can to minimize it, including giving up 5-10% MPG. This is my opinion of course.
• Normal temp on flat lands and low elevation in your 1:1 gear is ~196F. That will creep up a few degrees with elevation and very high ambient temperatures (100F+) but so long as you maintain that gear with a decent speed to maintain airflow it won't change. If you're seeing much over 200F when in your 1:1 gear on flat-ish highway that's a concern. In general you shouldn't see >200F unless you're in OD.
• Your A/T pan (A/T temp #1) and A/T torque converter (A/T temp #2) will match in the above 1:1 scenario. TC will heat up first when it unlocks or downshifts, and the pan will follow. Cooling temp and Engine Oil temp in my experience are ALWAYS between 196F (normal) and ~200F (steep grades, low gears).
• If you run in OD gears the torque converter generates a lot more heat. Without a trailer you'll run at a similar ~195F cruising on the highway. With a trailer you'll run about 5-10F hotter normally on flat highway, If the TC has to regularly unlock and/or downshift on any sort of incline (even an overpass) you will quickly heat up into the 210-220F range.
• Transmission fluid is circulated by engine RPM. There is no A/T fluid pump. Higher RPMs will move fluid through the system faster and cool your transmission better.
  • Keep your truck in gear and RPMs up even when descending. Higher gears/lower RPMs will increase the transmission temp even downhill as fluid circulation speed slows. I actually coasted down a big mountain pass for a bit in Neutral and my transmission temps increased to ~220F before I put it back into gear and brought the temp down.
• Your engine produces more torque at higher RPMs. The sweet spot for power, mileage, etc when towing is around 3000 in my experience. 3500 is where the power really kicks in,. The 3UR has a lot of grunt and will pull at lower RPMs, but I'm always shocked how much faster I can accelerate to pass someone in 4th gear when going from 65-75 than from 55-65.
  • Speaking of mileage, I've seen very little different between 4th, 5th, and 6th when towing. But I do often see dramatic temp differences.
• Bigger tires in particular will reduce RPMs and require using lower gears (or will unlock the TC if in OD) more often
• You need to maintain engine RPM when climbing mountains and towing. Don't be scared to downshift. I've pulled my trailer over Monarch Pass a couple times and the transmission was cooler at 5000 RPMs in 2nd gear @ 45mph than in lower RPMs in 3rd.

Disclaimer: All of my experience is fully laden (7500-8300#) with a 5000 or 6000# trailer. Tire sizes have varied from stock Bridgestones to 34" A/Ts, with and without bumpers and lift, etc. I cruise at 75mph for hours when towing. I'm not an expert, but I've put enough miles on my setup I'm very comfortable with it. YMMV.

 

[rscoleman]

I pull a boat every 2 to 3 weeks. 3500lb. I turn on ECT PWR button and put trans in 6th. Have had zero issues. Can run 80mph like that all day long (not advising you to do this). Gas mileage goes to less than pot. I have pulled a 5000 and 7000 lb using same set up and once again zero issues. I have 2016 with 8 speed.

 

[GordJ]

@Hants
I'm +1 with @Sandroad. 6th gear on the 8 speed, 4th gear on the 6 speed. Those are the 1:1 gears - anything above is an overdrive. (IIRC the manual in the 2008-2015 says you can run in 5th... not sure if they say 7th is OK for the 2016+ though). The manual says not to use your highest gear(s) when towing.

.

Linux, where in your manual is this reference?
The only instructions that I can find for my LC is “in order to maintain engine braking effiency when driving on a long steep downgrade, do not use overdrive. Transmission shift range must be in “4”, in”S” mode. My translation is “downshift when going downhill”to maintain proper speed.
The LX has essentially the same “tips” as the LC so I’m not sure why it is so constantly stated that it says to drive in “S” unless they have changed the manual for other years? I have always towed in “D” and downshift to slow down, whether on hills or coming to a stop.

 

[linuxgod]

Linux, where in your manual is this reference?
The only instructions that I can find for my LC is “in order to maintain engine braking effiency when driving on a long steep downgrade, do not use overdrive. Transmission shift range must be in “4”, in”S” mode. My translation is “downshift when going downhill”to maintain proper speed.
The LX has essentially the same “tips” as the LC so I’m not sure why it is so constantly stated that it says to drive in “S” unless they have changed the manual for other years? I have always towed in “D” and downshift to slow down, whether on hills or coming to a stop.

You're correct it doesn't say "never use 6th gear". Mine says "to maintain engine braking efficiency and charging system performance..." It says not to use "D" when engine braking, then has a separate line where it says to use 5th gear. See bullet #6 below below.

You could interpret that to mean "use 5th gear only when engine braking", or "use 5th gear when towing, and when engine braking you need to use "S" mode". Thing is, saying "don't use "D" when engine braking" is redundant since you really can't use "D" to engine brake as when you let off the throttle the ECU will cut fuel and the RPMs will drop off... so to engine brake you HAVE to use 5th gear, or lower.

Granted Toyota also says don't use cruise control when towing and don't drive above 65mph and yet I routinely do 75 on those 80mph highways out west with cruise control set...

Interpret the above manual page as you see fit. I speak from 5 summers and ~20k miles of trailer towing experience with a 2013. The 8 speed may behave differently. I encourage everyone to get a good OBD2 reader and monitor both transmission temp sensors while towing using various different strategies and then record what their experiences are. And for all my prior experience, I'm swapping to 4.88 gears shortly so I'm effectively going to have to re-test all of my theories and experiences with the engine in a different RPM band soon.

 

[catastrofe]

Hello everyone. Those of you that tow a small trailer with your cruiser, what gear do you leave it in? Do you just leave it in Drive or do you put the transmission in manual mode and select a gear? I kept the transmission in 6th gear and that seemed to be fine running 60 to 65 on the highway.

View attachment 2600550

Twin sons of different mothers...

I’ve been towing in S6 based on the manual and comments regarding reduced heat when the TC is locked. I just got my OBD reader configured and will compare “S6” vs “D” for transmission temps. From what I’ve seen so far (not towing) the TC locks just as often in “D” as it does in “S”

 

[linuxgod]

Twin sons of different mothers...

I’ve been towing in S6 based on the manual and comments regarding reduced heat when the TC is locked. I just got my OBD reader configured and will compare “S6” vs “D” for transmission temps. From what I’ve seen so far (not towing) the TC locks just as often in “D” as it does in “S”

View attachment 2602295

S vs D won't change the lockup, it just limits the max gear. Meaning S8 and D act the same way (or at least on the 6-speed S6 and D are identical). But S6 is your 1:1 gear so the TC will stay lock and stay locked whereas in S7 or S8 it will unlock before downshifting and may not necessarily engage right away when upshifting if there's a load on the transmission.

The TC is always unlocked in lower gears.

Side note: On the 6 speed if your A/T temp light comes on (at ~305 F, I believe) the transmission will limit the vehicle to 3rd gear until the temp drops below ~270F. I assume it's similar on the 8 speed and will limit you to a lower unlocked gear (which forces fluid through the radiator faster) but I've not dug into the FSM to confirm that.

 

[Hants]

This is the ODB monitoring screen I use. Blue ring is TC lockup.

@linuxgod My experience towing with this setup is A LOT less than yours, but mirrors your observations.

Only difference is I use D when towing except when I need S - and I have gauges to know when I need it.

Generally 6 or 7 when towing, but I have seen 8. The 8 speed transmission will lock the TC down to 2nd gear (yes, I have seen that).

I aggressively downshift on steep grades to ensure engine braking (down) and TC lockup (up).

You’re spot on with the RPM bands, in my experience.

 

[catastrofe]

This is the ODB monitoring screen I use. Blue ring is TC lockup.

@linuxgod My experience towing with this setup is A LOT less than yours, but mirrors your observations.

Only difference is I use D when towing except when I need S - and I have gauges to know when I need it.

Generally 6 or 7 when towing, but I have seen 8. The 8 speed transmission will lock the TC down to 2nd gear (yes, I have seen that).

I aggressively downshift on steep grades to ensure engine braking (down) and TC lockup (up).

You’re spot on with the RPM bands, in my experience.

View attachment 2602379

Nice layout! Here’s mine.

 

[catastrofe]

S vs D won't change the lockup, it just limits the max gear. Meaning S8 and D act the same way (or at least on the 6-speed S6 and D are identical). But S6 is your 1:1 gear so the TC will stay lock and stay locked whereas in S7 or S8 it will unlock before downshifting and may not necessarily engage right away when upshifting if there's a load on the transmission.

The TC is always unlocked in lower gears.

Side note: On the 6 speed if your A/T temp light comes on (at ~305 F, I believe) the transmission will limit the vehicle to 3rd gear until the temp drops below ~270F. I assume it's similar on the 8 speed and will limit you to a lower unlocked gear (which forces fluid through the radiator faster) but I've not dug into the FSM to confirm that.

I’m pretty sure I’ve seen the TC lock in gears below 6 in “D”. Haven’t driven much in “S” with my OBD layout.

 

[Artie]

I don’t think I can avoid the obd scanner rabbit hole any longer... anyone want to save me from this journey by suggesting their favorite or shall I stay up past my bedtime and order several to test on my own

editing to add that I found that I’m already watching this topic on another thread so I’ll go through it now... this forum is great.

 

[catastrofe]

I don’t think I can avoid the obd scanner rabbit hole any longer... anyone want to save me from this journey by suggesting their favorite or shall I stay up past my bedtime and order several to test on my own

editing to add that I found that I’m already watching this topic on another thread so I’ll go through it now... this forum is great.

I bought this one as I wanted a unit that worked with iOS via BT (some iOS compatible are only WiFi I believe). It comes with a “free” enhancement pack so you can get the Toyota specific PIDs.

OBDLink MX+ OBD2 Bluetooth Scanner for iPhone, Android, and Windows Amazon product ASIN B07JFRFJG6