Ok cool. I have an ELM327 module and paid for Fusion so I’ll probably just buy the extra parameters from Fusion at this point. Good to know for next time!
Towing with a 200-series Toyota Land Cruiser (4 Viewers)
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Ah, I can feel that anxiety…
Converter at 230° is an attention grabber, 245° I’m considering options. Those 2nd gear converter lockup climbs are my least favorite.
That’s some decent engine oil temp as well as coolant. It’s extremely rare for my coolant to get over 191°.
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I’ve had similar experiences. Usually higher ambient temps though. My worst was about 5.5 mpg adjusted. Yes you read that right. 6 speed but I was basically in 3rd or 4th a bunch of the time to hold 60 in some heavy crosswinds. Being regeared I can normally run in 5th.
2HundyJTex
SILVER Star
And ICYM, there’s a whole thread on this here:
DIY Smartphone Scan Gauge - OBD Fusion
Having spent some time messing with an OBD-II smartphone monitor app on several long road trips, I think this topic deserves its own thread. Specifically using OBD Fusion to monitor the plethora of info available on the OBD-II data port of the vehicle. I can't take credit for this, but would...
forum.ih8mud.com
Can you remind us, besides the 315s, do you have any other mods (bumpers, skids, etc.)?
sounds about right. elevation plays havoc on temps, and to add a lower power level due to o2 density. The LC had a workout
Just skids, no bumpers. Totally stock suspension
I had the same issue the first time I towed when my truck was bone stock. I was towing from my house here near Park City UT down to Valley of Fire in NV, and was fighting a really strong headwind. Difference was, it was more 45F to 60F outside during that drive if I remember right. I got stuck in 3rd and 4th gear and same thing, transmission got up in the 230 range on the flats and when I had to grind up a big grade I believe I hit 243F on Trans Oil Temp 1.
So it’s not because it’s modified. The 315/70’s probably don’t help, but it’s a problem on the bone stock truck too.
I’d be fine with it if it was only when I was pulling grades, it’s the fact that the temps remain elevated even on the flats because I’m in 4th with the TC unlocked.
Thanks. I’ve hit the 240° range in the converter pulling 5-6,000 pounds but only on steep grades like Douglas pass in Colorado:
I’ll maintain in the low 200°s with a 15-25 MPH headwind @ 65-70 MPH through central Utah (not like what you just had). I’ve recently added full skids and so we’ll see how much that affects temps this summer. My guess is it will be noticeable.
Sure, the transmission and everything can take it but the ATF change interval certainly shortens.
Do you know if the VFtuner will allow you to force lockup in 3rd and 4th?
I need to try it. It has the tables for TC lock and unlock, I just need to flash it and try
It does sound like a difficult tow situation and I've definitely been there in unfavorable gusty winds. Been there in a solo car too with RTT, heavily laden for extended trips where winds become a factor. Aero is near the top of my list as I consider trade-offs with mods and a big reason I strive to keep stock tupperwear. Slowing down is sane compensation when winds are working hard against you. If it's 15-25mph headwinds on top of 70mph travel speeds, that's potentially into 85-95 relative aero loads which gets insane compounded with trailer loads.
While the 8-speed has great deep gearing, your tow performance is surely impacted by upsized tires. It's almost a 10% change in gearing. While you can always grab a lower gear, the torque converter logic is going to be outside of its tuning as you're finding. Torque converter lockup in itself can result in 1-2 MPG loss on longer stretches. I do hope we'll find more flexibility for transmission tuning in the near future. I think for now, all we have is real mechanical re-gear changes or possibly even a lock-up kit?
Personally, those transmission temps are fine and nowhere near the danger zone for modern fluids, even for extended legs. Towing is work and demands hp which create more load and heat. Slowing down is always a reasonable option but there's already compensation logic to protect from the real temps that destroy fluid and hardware. It can get to a point that the computer will aggressively lockup in low gears, all the way down to even 2nd (in my 6-speed) where temps will moderate significantly. And sure, you'll want to be on the severe duty service interval with significant towing. You can add a secondary aux tranny cooler, which I did not so much for this situation, but for extended climbs towing 8k lbs. That won't solve the MPG efficiency though as lockup is the key factor there. Yet lockup (or the lack thereof), is a tool the transmission uses to create more gearing (as demanded by the gas pedal) even in gear if that makes sense. The added slip is an intermediate gear between physical gears.
Back to aero impacts as we talked about this in another thread, but as much as you can, you want your trailer level at freeway speeds when AHC lowers, to maximize aero efficiency.
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This is slowed down. I was doing 55-60mph in 65-70mph posted zones because I didnt want the transmission temps consistently above 230F.
And yes, the tires are like 8% larger, but that doesnt mean I could have run in 5th gear had the stock tires been on. I was in 4th, bordering on needing to be in 3rd.
The TC lockup tables could be tailored to take advantage of what you are talking about. Throttle position is accounted for and so you could keep the TC locked below a certain threshold and then unlock it only if you cross a certain threshold. The problem right now is that the TC NEVER locks up in 3rd or 4th gear, ever. You can be barely on the throttle in 4th and it just keeps it open.
Yup. It's a challenging to situation and there will be days like that.
I'm just short of factory gearing with my mods and re-gear. There are stretches I'm doing 3rd (~4.8 overall gearing), which is between your 3rd and 4th (5.4 and 4.2 overall gearing respectively). Mine also doesn't normally lock in 3rd unless tripping temp thresholds which is a combined trip logic of ATF over 266°F and coolant over 203°F. Probably similar thresholds on the 8-speeds which I couldn't find ATM.
ATF is a consumable that can be changed. Gas is a consumable to be literally pissed into the wind. So is the vehicle ultimately. This is all within the realm of the normal so use what you got and work through it. All vehicles will be challenged and heat up doing work like this. Even an HD truck.
If you're looking for a solution, I get the sense an Airstream has much better aerodynamics and the fuel efficiency (can that word even be used when towing?) does show that to degree. Change the fluid more often. Re-gear. Tune the ECU. Let off the gas some more.
I was just looking in VFTuner and it looks like it enters transmission hot mode when the ECT is >98C and Trans fluid temp is >125C.
Well, I just flashed a tune to lock up the TC in 4th gear. To late tonight to take it for a spin but I will try tomorrow and report back with more details.
No luck. But there are like 12 lock/unlock tables for different conditions and just driving around town I was having trouble getting the transmission temp above 150F. I wonder if it was stuck in "cold shift" mode and I simply edited the wrong table.
I did notice when I drove to Boise in late March that the transmission temp never got over like 150 or something even after driving for hours at 80mph.
I’ve experienced 150°s as a somewhat normal operating temp when conditions are tame, especially when not towing.
altitude is a killer.
225 sustained is fine for synthetic dexron 6, WS and others,,,,sustained 250 is right there at the flash point....beware. intermittent at 250 is ok
The Yota cooler works pretty good.......
FrazzledHunter
SILVER Star
I'm about to tow at high altitude this June so I'm asking about this and probably missing something so apologies in advance.
How does altitude affect the transmission temps? Altitude affects combustion, right?
I get that at high altitudes the engine works harder, so the engine coolant gets hotter etc...
I've experienced that first hand!
So:
- At higher altitudes the engine is hotter and the trans cooler in the radiator doesn't cool the trans as well.
- The air is less dense at high altitudes and the cooler in front of the radiator doesn't work as well.
It’s due to the loss of power so the torque converter will unlock more during climbs to help with the loss of torque, this raises the transmission temps. Once the converter temp climbs up to the 230 range this will cause the pan temp to start heating up. It can snowball from there because the harder everything works the hotter it gets. RPM’s are higher looking for more power to turn the transmission.I'm about to tow at high altitude this June so I'm asking about this and probably missing something so apologies in advance.
How does altitude affect the transmission temps? Altitude affects combustion, right?
I get that at high altitudes the engine works harder, so the engine coolant gets hotter etc...
I've experienced that first hand!
So:
Are those the issues with altitude and trans tamps?
- At higher altitudes the engine is hotter and the trans cooler in the radiator doesn't cool the trans as well.
- The air is less dense at high altitudes and the cooler in front of the radiator doesn't work as well.
Once the converter temps get hot enough the computer will allow lockup in lower gears which sheds heat very rapidly.
If you have the obd fusion gauge set up you can keep an eye on things and adjust your driving accordingly. However, this is a good example of the bliss of ignorance because you’ll be watching the temps climb and there is a direct connection between the torque converter temp and your anxiety.
If you see a climb coming up don’t wait to build speed, go into it gaining speed if possible and try to drag out shifts. Shifting manually here will help you, try and achieve lock up and keep it there until your RPM’s are high enough to maintain momentum when it shifts into the next gear.
Depending on your weight and the altitude a slow 2nd or 3rd gear climb at 40 mph isn’t unheard of. Once you get a few of these under your belt you’ll have the hang of it.
Also, you can always pull of at a vantage point and take a break, they are usually around at convenient spots.
I'm about to tow at high altitude this June so I'm asking about this and probably missing something so apologies in advance.
How does altitude affect the transmission temps? Altitude affects combustion, right?
I get that at high altitudes the engine works harder, so the engine coolant gets hotter etc...
I've experienced that first hand!
So:
Are those the issues with altitude and trans tamps?
- At higher altitudes the engine is hotter and the trans cooler in the radiator doesn't cool the trans as well.
- The air is less dense at high altitudes and the cooler in front of the radiator doesn't work as well.
While we like to stress about temps, the reality is that the 200-series is a very well developed design validated to do even the heaviest work. There isn't an overheating problem to speak of. ATF heating up is normal. The ECU is equipped to utilize the fluid to its advantage (unlocking is a feature!), while managing fluid temps within its operating range.
Even as many of us mod in ways that are not conducive to heavy towing and create perceived "issues", it still hauls the mail in the most stressful use cases. That's why we own these things.
