GX460 Transmission fluid cooler

[Acrad]

Are you monitoring both pan and TC outflow sensors? It could be basing it on TC outflow which would be hotter.

Not aware of a non-TS reset method.

What number are you currently displaying for thermal degradation?

It is possible there is other sensor log data factored in other than just the AT temps. Just speculation though.

 

[thescreensavers]

Are you monitoring both pan and TC outflow sensors? It could be basing it on TC outflow which would be hotter.

Not aware of a non-TS reset method.

What number are you currently displaying for thermal degradation?

I am looking at both. My thermostat is pinned and I have a Hayden 678. now that its warmer out 90s it's seeing low 170s while cruising torque converter locked. With it unlocked I've seen it hit it's mid 180s maybe touching low 190s.

It's at 30,300 ish 53k miles. I'm not sure if 2020+ have a different programming of the thermal degradation. Any idea what happens when it hits that 50k threshold?

 

[Acrad]

It doesn’t appear to cause any alerts as someone at bottom of this thread had over 65k

One thing I’m not sure about but have always wondered if Lexus modified TC lockup programming in later years to attempt more lockup. This could account for some reporting lower overall temps than what I see reported in earlier years.

#ATF #Thermal #Degradation Estimate - share your data - #transmission - ClubLexus - Lexus Forum Discussion

GX - 2nd Gen (2010-2023) - #ATF #Thermal #Degradation Estimate - share your data - #transmission - Not sure how many folks have an OBDII reader to see the data, but was curious to compare ATF thermal degradation numbers. Would be great to include driving conditions if you share. Here's mine...

www.clublexus.com

 

[Wildcat Walker]

@Rednexus I'm sure the Hayden is a fine product, they were back in 2009 when I was selling them at Slow-Reilly's. I got 8.8 mpg on my towing journey, that's with 93 octane. I would love to do some Heat Transfer calcs comparing a few of the HX's shown in this thread. Need to know the flow rates of fluid to the cooler specific heat of Toyota WS, Temps, air velocity, etc. . I could setup an apples to apples calc with a few assumptions that would give an idea of just how sufficient or overkill any of the options are. Overall the goal is to exchange heat faster than the trans can create it across a range of external conditions. Maybe some additional magnets on the exterior of the pan and just a cooler with no inline filter would provide the best benefit in terms of heat transfer and cost. A finned pan would provide additional HT, assuming the air moving across it had a high enough Delta T. This could get involved pretty quick. The idea behind running a beefy cooler is you know it's grossly oversized and up to the task.

@Acrad I didn't see any info on how to access the datapoint, I'm assuming I need a high dollar scan tool. I'm not certain what value the metric holds. It must be some degradation value based off laboratory testing. The calculation is a basic linear equation in the form of y=mx+b, it's going to be a straight line sloping up and to the right if we assume A and B are some positive values. The displayed value is between 0 and 65535, note that at a displayed value above 50k the fluid is considered degraded. It would be nice to know what parameters A and B represent here. As long as one of those parameters is non zero, then the displayed value is going to increase. Thinking about this a little more, it looks like the equation equals a degradation value in which A is a temperature parameter and B is a historical component. The degradation range starts at 0, likely when the estimate is reset. The fluid must always degrades at some rate, and this rate increases with respect to temperature. At some temperature the degradation rate would be vertical, and logically the degradation rate could never be negative. It could be that the linear equation is just the important part of the full degradation curve, that is, a direct line from zero (or historical reference point) to where the degradation of the fluid currently is. It is possible that the memory component of this feature doesn't have enough capacity to store all the previous trips, and the B is the start point from the last trip. If the system knew the previous Y, the previous A and B values, it could effectively sum the past trip to the future trip with only a few data points instead of storing the long term curve. The only way this data point would be useful in my case would be if I had a "normal" curve to compare to or if the degradation value was unreasonably high for my current mileage. I do think that the degradation value would become even less meaningful after a fluid change, as the documentation you provided states that if a minimum of 50% of the fluid was exchanged, the reset procedure should be performed. In my case, I'm on the factory fill, so the data would be more useful as the degradation would have occurred to 100% of the fluid.

Why the hell cant Lexus just put a beefy cooler on these trucks to begin with? Sheesh.

 

[Wildcat Walker]

Have we found a way to reset that without techstream? My 2020 is still counting thermal degradation even though fluid temp hasnt really gone north of 180F. It's around 30k right now and I'm about to dona fluid exchange.

That's not how the calculation works. Degradation is always going to occur, regardless of if you're below 180*F or not. ATF is not an infinite life fluid, the degradation counter will always be summing when the conditions are met, i.e. running/driving. What I find curious is that at a degradation value of 50k, the fluid is considered "degraded" yet the counter continues to count up into the 60k range, why? Does an indicator or warning message illuminate at 50k? Was this feature just a summer intern project that has little practical use? Even worse is that after an initial fluid change and reset, the degradation value appears less accurate depending on the amount of fluid exchanged. Maybe the calculation changes after the first reset and the assumption is that the amount of fluid exchanged is that of a typical drain and fill procedure? Maybe the degradation value doesn't start at zero when reset? Need more info.

 

[thescreensavers]

@Rednexus I would love to do some Heat Transfer calcs comparing a few of the HX's shown in this thread. Need to know the flow rates of fluid to the cooler specific heat of Toyota WS, Temps, air velocity, etc. . I could setup an apples to apples calc with a few assumptions that would give an idea of just how sufficient or overkill any of the options are. Overall the goal is to exchange heat faster than the trans can create it across a range of external conditions. Maybe some additional magnets on the exterior of the pan and just a cooler with no inline filter would provide the best benefit in terms of heat transfer and cost. A finned pan would provide additional HT, assuming the air moving across it had a high enough Delta T. This could get involved pretty quick. The idea behind running a beefy cooler is you know it's grossly oversized and up to the task.

The only way you are going to figure out if one Heat exchanger is better than the other is through empirical testing. I believe that's not a great use of time and money, a Hayden 678 is cheap and drops temps ~20-30F. Best thing you can do is tow your load and check temps. If temps are not in check go to a larger cooler or get better airflow.

That's not how the calculation works. Degradation is always going to occur, regardless of if you're below 180*F or not. ATF is not an infinite life fluid, the degradation counter will always be summing when the conditions are met, i.e. running/driving. What I find curious is that at a degradation value of 50k, the fluid is considered "degraded" yet the counter continues to count up into the 60k range, why? Does an indicator or warning message illuminate at 50k? Was this feature just a summer intern project that has little practical use? Even worse is that after an initial fluid change and reset, the degradation value appears less accurate depending on the amount of fluid exchanged. Maybe the calculation changes after the first reset and the assumption is that the amount of fluid exchanged is that of a typical drain and fill procedure? Maybe the degradation value doesn't start at zero when reset? Need more info.

Yes but the item is specifically called "Thermal Degradation" its not a far stretch to assume its thermally related. Clearly its still counting even if temps are lower than normal operating temps so it likely has other factors involved. Auto Transmissions in general adapt to wear overtime so imo it is likly being used somewhere in some caclulation to alter its shift strategy/behavior.

 

[Acrad]

@Wildcat Walker - I’m not sure if Torque can see datapoint but OBD Fusion or Link can

Techstream not required to access

#OBD #Fusion / #Link - Vehicle #Diagnostic Tool - ClubLexus - Lexus Forum Discussion

GX - 2nd Gen (2010-2023) - ?? #OBD #Fusion / #Link - Vehicle #Diagnostic Tool - PID Screenshots (https://photos.google.com/share/AF1QipPOIZn6WWqVG3YVNnYwcD3IvfbLHcnWJ8RGn5eWAMMeIVz0B42IqGbS2fuglaMJ0A?key=YTNFUjRxc0NCS3ZVaTRhZm4zdVJCUnVuYWdwdlJR) This app has been been discussed in a couple...

www.clublexus.com

 

[Wildcat Walker]

The only way you are going to figure out if one Heat exchanger is better than the other is through empirical testing. I believe that's not a great use of time and money, a Hayden 678 is cheap and drops temps ~20-30F. Best thing you can do is tow your load and check temps. If temps are not in check go to a larger cooler or get better airflow.


Yes but the item is specifically called "Thermal Degradation" its not a far stretch to assume its thermally related. Clearly its still counting even if temps are lower than normal operating temps so it likely has other factors involved. Auto Transmissions in general adapt to wear overtime so imo it is likly being used somewhere in some caclulation to alter its shift strategy/behavior.

The only way? The math comes first, LMTD or energy balance. I've done a ton of energy calculations, and specifically heat transfer calcs, without any tangible components being involved. An easy comparison of HX's could be made using a just a few known or even assumed values. Sure, empirical testing would give us some exact numbers in lab conditions, but I don't think anyone here is going to go to that much effort. There's always Ansys if you wanna dive that deep.

I don't think it is clear, or a valid assumption, that the degradation value is climbing when the fluid is below "normal" temps. The fact is, we don't have enough information to know the full algorithm. The equation provided is only in two variables, thus the plot provided by the inputs to the equation is equally dimensioned. In my mind I am seeing this as an x-y plot with degradation being the y values, and time being the x values. There is a curve on this plot, from zero, with varying levels of positive slope (A*256), or even near zero slope (little to no thermal degradation, A=0). This is why in my 5 minute analysis I stated that some conditions must be met in order for the counter to be increasing. It does not make sense that the fluid would become less degraded over time, thus no decreasing slope and no decreasing degradation value. I think its safe to assume that if the engine is on, and the pump is turning, degradation is occurring at SOME rate, even if that rate is infinitesimally small.

Sorry if I wasn't clear before, Heat Transfer, Fluids, and Calculus are not subjects easily conveyed in a few short paragraphs.

 

[suitcase]

Just for fun, here are the AT temps I measured on a recent trip going from Bishop, CA (395N) up Tioga Pass (120) and into Yosemite Valley.
Max Pan: 207F
Avg Pan: 194F
Max TC: 223F
Avg TC: 201

GX is outfitted with the OEM AT cooler. I wasn't towing anything and nothing on the roof, but truck was packed with camping gear, big cooler, and two paddle boards.

 

[r2m]

Just for fun, here are the AT temps I measured on a recent trip going from Bishop, CA (395N) up Tioga Pass (120) and into Yosemite Valley.
Max Pan: 207F
Avg Pan: 194F
Max TC: 223F
Avg TC: 201

GX is outfitted with the OEM AT cooler. I wasn't towing anything and nothing on the roof, but truck was packed with camping gear, big cooler, and two paddle boards.

Okay, you got me, I'm stumped. Nothing on the roof, but you had two paddle boards?
Were the paddle boards inflatable??

 

[thescreensavers]

The only way? The math comes first, LMTD or energy balance. I've done a ton of energy calculations, and specifically heat transfer calcs, without any tangible components being involved. An easy comparison of HX's could be made using a just a few known or even assumed values. Sure, empirical testing would give us some exact numbers in lab conditions, but I don't think anyone here is going to go to that much effort. There's always Ansys if you wanna dive that deep.

I don't think it is clear, or a valid assumption, that the degradation value is climbing when the fluid is below "normal" temps. The fact is, we don't have enough information to know the full algorithm. The equation provided is only in two variables, thus the plot provided by the inputs to the equation is equally dimensioned. In my mind I am seeing this as an x-y plot with degradation being the y values, and time being the x values. There is a curve on this plot, from zero, with varying levels of positive slope (A*256), or even near zero slope (little to no thermal degradation, A=0). This is why in my 5 minute analysis I stated that some conditions must be met in order for the counter to be increasing. It does not make sense that the fluid would become less degraded over time, thus no decreasing slope and no decreasing degradation value. I think its safe to assume that if the engine is on, and the pump is turning, degradation is occurring at SOME rate, even if that rate is infinitesimally small.

Sorry if I wasn't clear before, Heat Transfer, Fluids, and Calculus are not subjects easily conveyed in a few short paragraphs.

Oh I am well aware of the methods you speak of I have personally done them (FSAE in College) albeit a bit ago. What I am getting at, is that all those calculations at the end of the day is a mental stroking. If you already got a spreadsheet setup and it wont take you all that long to get a "Number" that sounds great but.... Your assumptions (by my assumptions ) would be equal fluid flows (Air/ATF) so at the end of the day what are you trying to get too? Larger cooler will reject more heat on the vehicle if they are all equal thickness. If you are trying to somehow optimize then empirically you do not have enough inputs though im sure you can make some assumptions there. But then just get a thermostat thats at your "Optimal temp".

Ive looked at used thermostats on ebay actually I want to open it up to see what thermostat is in there so potentially we can change it out to open a bit earlier and not need to have the thermostat pinned.

And another side note If you dont want to think about it the OEM setup is optimized from the MFG

 

[Rednexus]

The only way? The math comes first, LMTD or energy balance. I've done a ton of energy calculations, and specifically heat transfer calcs, without any tangible components being involved. An easy comparison of HX's could be made using a just a few known or even assumed values. Sure, empirical testing would give us some exact numbers in lab conditions, but I don't think anyone here is going to go to that much effort. There's always Ansys if you wanna dive that deep.

I don't think it is clear, or a valid assumption, that the degradation value is climbing when the fluid is below "normal" temps. The fact is, we don't have enough information to know the full algorithm. The equation provided is only in two variables, thus the plot provided by the inputs to the equation is equally dimensioned. In my mind I am seeing this as an x-y plot with degradation being the y values, and time being the x values. There is a curve on this plot, from zero, with varying levels of positive slope (A*256), or even near zero slope (little to no thermal degradation, A=0). This is why in my 5 minute analysis I stated that some conditions must be met in order for the counter to be increasing. It does not make sense that the fluid would become less degraded over time, thus no decreasing slope and no decreasing degradation value. I think its safe to assume that if the engine is on, and the pump is turning, degradation is occurring at SOME rate, even if that rate is infinitesimally small.

Sorry if I wasn't clear before, Heat Transfer, Fluids, and Calculus are not subjects easily conveyed in a few short paragraphs.

You seem to be a mechanical engineer . I'm a geotechnical engineer. Much of I do in my field is semi-empirical, where we have equations that are based in theory but modified with empirical factors that have been developed using actual observations of performance in the real world. We deal with soil, rock, and groundwater, which natural substances in a natural system, and can be highly variable between sites and even within a site. Our profession is somewhat similar to being a meteorologist - we do our best job to analytically predict the behavior of a natural system - but there is always a large amount of uncertainty in our predictions, and limits on how close our analyses can ever come to representing reality (which is why we often rely on judgement as much as analytics and predictive modeling).

Back to the Hayden - I would certainly be interested in seeing the results of your calculations. My Hayden has been installed since 2021/2022, so I have a pretty good empirical evidence base on how the cooler performs. The only time I've gotten above 200F with the Hayden was climbing a long 4LO mountain pass in CO where it slowly crept up to about 225F. I honestly think the problem is due to the OEM mechanical fan on these not moving a lot of air on low-speed crawls. Putting the rig in 1st gear low range (giving it more engine/fan speed) rapidly decreased the trans temp. The lockup switch would have fixed the issue, but wheeling with the TCC locked in 1st gear will mean stalling the rig when you com to a stop. I recently installed a CSF radiator which I hope that will provide even more cooling capacity.

 

[suitcase]

Okay, you got me, I'm stumped. Nothing on the roof, but you had two paddle boards?
Were the paddle boards inflatable??

Yes, the paddle boards were the inflatable type. I used the S mode to help with going up the passes and slowing down on the descents. I had in the back of my mind to record the ATF degradation level before the trip to compare, but forgot to check.

 

[BC11SVT]

Have we found a way to reset that without techstream? My 2020 is still counting thermal degradation even though fluid temp hasnt really gone north of 180F. It's around 30k right now and I'm about to dona fluid exchange.

Many scanners can reset the ATF thermal degredation estimate.
I used a Launch Creader Elite V2.0 to reset it

 

[Acrad]

@BC11SVT Does that do TPMS programming as well on the 460? I currently just use TS

 

[jeremy j]

@BC11SVT Does that do TPMS programming as well on the 460? I currently just use TS

I have one and it does.

 

[WTITW]

You sure

@WTITW Actually one is pan and two is TC outlet

Sure about that? In obd fusion my at2 is the one thats always higher than the at1, much more erratic and drops dramatically when I find lock up with at1 coming down slowly.

 

[thescreensavers]

Back to the Hayden - I would certainly be interested in seeing the results of your calculations.

I recently installed a CSF radiator which I hope that will provide even more cooling capacity.

Hah I installed one and it runs cooler, calculations done

I have seen from a few folks with CSF radiator without an added cooler(or Hayden) it does seem to run a little cooler than stock.

 

[Rednexus]

Hah I installed one and it runs cooler, calculations done

I have seen from a few folks with CSF radiator without an added cooler(or Hayden) it does seem to run a little cooler than stock.

Such is the value of empirical observations . I often encounter other engineers whose analyses clearly don't reflect reality (i.e., a structure that has fine performance is at risk of imminent failure). My usual response is that their calculations are clearly wrong, yet they tend to believe their calculations over reality!

 

[Acrad]

@WTITW Positive… TC outflow (Sensor 2) is always hotter than the pan.. I’ve never seen it otherwise on my rig anyway. Your temp observations are what I would expect to see.