At what transmission temperature should I be concerned when towing (1 Viewer)

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2016 LC200 and towed my 4600 pound travel trailer with it a few weeks ago. Very nice. I don't want to lump multiple topics in this thread but I now have an ODB diagnostic scanner and the Car Scanner app for my ios device. The reason I purchased these is because I read that when towing one needs to keep an eye on the transmission temp and the gear the transmission is hunting for on hilly terrain. So I want to monitor the transmission temp and current gear (assuming that seeing the gear changing indicates some transmission hunting) while towing. Aside from the fact that at the moment I can't seem to monitor these things (just need more time to figure it out), what temperature range and high point should cause me to be concerned about the transmission temp?
 
Things can and will get hot under tow. Even under unexpected situations like engine braking.

There's two temps and the one at the torque converter tends to be more dynamic, especially when the torque converter unlocks. I wouldn't be surprised to see this one into 240F under strenuous conditions and perhaps even higher.

Nominally, things are around 190-230.

If I had to identify a max where the driver should ease up, I'd say 260 or even 270 for the torque converter temp. Probably 240 for the more stable monitor. Though you won't likely see these temps towing 4600lbs as the Land Cruiser has robust cooling capacity.

I tow an 8k travel trailer, around 15k GCWR, on the regular for context. Over Sierras and Rockies. I'm on 35s, but re-geared to practically stock gearing. This is about as hot as things get and it's still within safe.

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Does the gear indicator on these actually report current transmission gear selection, or what you have it set to in "S" mode? (IE highest allowed gear)
 
Does your truck have manual shift. Using that when towing you can see the hunting. The manual also recommends that mode.
Unless you do heavy towing I'll not be concerned.
Now if you have the scanner you can play with it, off course.
 
2016 LC200 and towed my 4600 pound travel trailer with it a few weeks ago. Very nice. I don't want to lump multiple topics in this thread but I now have an ODB diagnostic scanner and the Car Scanner app for my ios device. The reason I purchased these is because I read that when towing one needs to keep an eye on the transmission temp and the gear the transmission is hunting for on hilly terrain. So I want to monitor the transmission temp and current gear (assuming that seeing the gear changing indicates some transmission hunting) while towing. Aside from the fact that at the moment I can't seem to monitor these things (just need more time to figure it out), what temperature range and high point should cause me to be concerned about the transmission temp?
I assume you know to tow in S6. That will do 2 things. It keeps the torque converter mostly locked up so it runs much cooler. And it keeps engine rpm in a range where maximum torque is available. That combination will greatly reduce any gear hunting.
 
Yes in a previous thread the folks on this forum explained how to set S6 for towing and the automatic will take care of the shifting. But.. when I towed in S6 we still had automatic shifting so assumed that there may still be some hunting..
 
Does the gear indicator on these actually report current transmission gear selection, or what you have it set to in "S" mode? (IE highest allowed gear)

It reports actual gear.

Yes in a previous thread the folks on this forum explained how to set S6 for towing and the automatic will take care of the shifting. But.. when I towed in S6 we still had automatic shifting so assumed that there may still be some hunting..

Yes, this is expected as S# does not select a gear, rather tells the transmission the highest gear to use. S6 means use any (lower) gear up to a highest of 6th gear. For those that have driven manual cars, perhaps downshifting is more intuitive. If you feel the engine lack in torque response or if the transmission is hunting, feel free to shift down a cog. Or let it do its thing. Would be worthwhile to practice however as downshifting for downhills is not so much just good practice, as it is imperative for safety when towing heavy. Even for 4600lbs.
 
Yes, I use downshifting. Also tow with my 06 Tundra and downshifting helps quite a bit on hills. On your ODB dashboard, is the circle around the current gear indicating that the TC is locked? I'm looking for this type of dashboard. Not sure I can get it with the Car Scanner app or that I need some specific advanced diagnostics to pick up that data.
 
Yes, I use downshifting. Also tow with my 06 Tundra and downshifting helps quite a bit on hills. On your ODB dashboard, is the circle around the current gear indicating that the TC is locked? I'm looking for this type of dashboard. Not sure I can get it with the Car Scanner app or that I need some specific advanced diagnostics to pick up that data.
 
Perfect!! Thanks.
 
I've only seen temps approach 245-250F when climbing steep mountain passes. Otherwise you will run in the 195-215F range if you keep the torque converter locked up and shouldn't need to worry. Anything over 240F starts to worry me. 250F is my personal danger zone, but it's based on my gut not any scientific evidence.

The A/T temp light will come on at ~304F I believe, and will go off around ~270F. I'd need to check the FSM to confirm the precise #s but that's within a few degrees. I interpret that to mean Toyota feels that anything 270F or lower is fine, that 270-304F is the yellow zone where you get a lot more wear but you can drive like that for thousands (if not tens of thousands) of miles before you need to do a fluid change, and that above 304F is bad and you should avoid it and do a fluid swap as soon as you can.
 
We are going to be pulling a TT ( GVWR 7400 lbs) on a long trip this summer and Im worried about the Trans temps in the 200 while towing. I have pulled with it once now right before the end of last season and I cut our trip short because I was worried about the pan temp running consistently at about 212-215. I kept the truck in 4th gear the entire time to keep the TC locked up as much as possible. I found the optimal speed to prevent shifting and still have power was between 67 and 70 mph. The reason Im nervous with these temps is we used to pull a smaller TT with my V8 4th gen 4R and I cooked the ATF after a trip with trans temps running between 215 and 220. I know these are two different transmissions but I can't imagine the 6 speed in the 200 would handle much more heat than the 5 speed in the 4R. Im honestly thinking at this point I may just sell the 4R and get a 3/4 ton truck to tow with because I love our 200 and I don't want to prematurely wear it out. I'd love to hear other peoples experience with the Trans temps while towing and if anyone has installed a secondary trans cooler. TIA
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We are going to be pulling a TT ( GVWR 7400 lbs) on a long trip this summer and Im worried about the Trans temps in the 200 while towing. I have pulled with it once now right before the end of last season and I cut our trip short because I was worried about the pan temp running consistently at about 212-215. I kept the truck in 4th gear the entire time to keep the TC locked up as much as possible. I found the optimal speed to prevent shifting and still have power was between 67 and 70 mph. The reason Im nervous with these temps is we used to pull a smaller TT with my V8 4th gen 4R and I cooked the ATF after a trip with trans temps running between 215 and 220. I know these are two different transmissions but I can't imagine the 6 speed in the 200 would handle much more heat than the 5 speed in the 4R. Im honestly thinking at this point I may just sell the 4R and get a 3/4 ton truck to tow with because I love our 200 and I don't want to prematurely wear it out. I'd love to hear other peoples experience with the Trans temps while towing and if anyone has installed a secondary trans cooler. TIAView attachment 2889147

I wouldn't sweat at 220F. There's plenty of margin beyond that. Here's a link to a hard tow test for the Tundra that has a similar drivetrain. Albiet without tranny cooler in the latest model years. Cheif Engineer states temps reached (246) are within design parameters.

Our cruisers are built for work. I truly believe that and use mine hard. We have bigger tranny coolers than the Tundra. Change the trans fluid on the higher duty cycle interval.

 
Plus, it wouldn't be secondary.. it would be.. tertiary? We already have two.

You'd have a hard time beating the stock 200-series trans cooler setup, between the ducting for the air/fluid cooler behind the grille, and the tremendous amount of BTUs that can be removed by the fluid/fluid cooler in the bottom tank of the radiator.
 
We are going to be pulling a TT ( GVWR 7400 lbs) on a long trip this summer and Im worried about the Trans temps in the 200 while towing. I have pulled with it once now right before the end of last season and I cut our trip short because I was worried about the pan temp running consistently at about 212-215. I kept the truck in 4th gear the entire time to keep the TC locked up as much as possible. I found the optimal speed to prevent shifting and still have power was between 67 and 70 mph. The reason Im nervous with these temps is we used to pull a smaller TT with my V8 4th gen 4R and I cooked the ATF after a trip with trans temps running between 215 and 220. I know these are two different transmissions but I can't imagine the 6 speed in the 200 would handle much more heat than the 5 speed in the 4R. Im honestly thinking at this point I may just sell the 4R and get a 3/4 ton truck to tow with because I love our 200 and I don't want to prematurely wear it out. I'd love to hear other peoples experience with the Trans temps while towing and if anyone has installed a secondary trans cooler. TIAView attachment 2889147
What happened to your 4Runner. The A750f it has is shared with the 03-07 100 series Cruisers.
 
I've been running at those temps for years now. Bought in 2016, pretty much have run 200-220F for 30k miles or so of towing.

Use 4th, keep the TC locked, do regular AT fluid changes, and I don't think you'll have an issue.

FWIW the AT temp light comes on at 304F and shut off around 270F. So Toyota doesn't seem to think it's bad to run the 6 speed AT at temps below 270F, apparently.
 
I just towed my 4200 lb travel trailer for the first time from Denver to Dillon, CO (~9k feet). Pan temps got up to about 215 and converter temp got up to 238 a few times. I wasn’t babying it but wasn’t pushing it to hard either. These are actually higher temps than I saw pulling the same trailer with my GX470 (with an upgraded trans cooler) but the LX570 did it sooo much easier and with power to spare :)
 

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