See if Jerry will loan you his switch since it seems to work perfectly for the desired on and off temps.
42RLE Transmission Temperatures?
- Thread starter Irun
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See if Jerry will loan you his switch since it seems to work perfectly for the desired on and off temps.
I'm sure I'm late to the party and don't understand all the finer points of this conversation, but it seems like you want the Derale to turn on when the inside of the trans measures 180 since the Derale has a 180 switch, when in reality the external Derale doesn't see a temp of 180 until around 200 internally. They read differently because they are measured from two very different locations.
Or are you thinking the 180 switch is faulty because it doesn't come on when you think it should? The problem here is that the only indication you have of the temperature at the Derale switch is when it turns on, which is presumed to be the temp the switch is rated at.
FWIW, I have a 32RH which has it's own temperature profile.....but I have a Hayden installed in front of my radiator (no additional fans), and the hottest my gauge has ever read was yesterday afternoon. It was 109F heading dead into the sun, and the pan mounted sensor read a steady 162F, did not go up even when stopped at extended red lights. It's been 105-112 the last two weeks and the gauge has consistently read in the 150-160 range. ¯\_(ツ)_/¯
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This is likely the route I will go. Similar weather but mine runs 180/190 with a new mopar radiator but no additional transmission cooler. Do you know the part number of the cooler you use?
Just a heads up, Mike has a lot going on with his Jeep. He has a setrab cooler in front of his radiator that used to be for his transmission but it now helps cool intake temps for his turbo so his use of derale is out of necessity not necessarily that it’s the best route
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It helps if we remind folks of the context each time we post. I'm pretty sure you have the 32RH and if so, the cooling needs of that trans are dramatically different than for the 42RLE.
I have two issues with the Derale switch.
1. Derale advertises that their switch turns on at 180* and that would be fine and dandy if it translated to the fan turning on when the sensor in the transmission reads 180*, but that's not the case (the fan comes on around when the pan reads temps of 200*).
See #2 below
2. The Derale switch does not repeatedly turn on at a specific temp. Sometimes it's on at 199* and other times it's not on when my temps are at 205*. That's not acceptable for this application especially when I haven't pushed the system offroading yet. My temp gauge allows me to know what my temps are at when the switch turns the fan on. I also know what the temps are at when the fan is not on but should be on (I've taken videos for Derale but they never got back to me so I haven't updated them yet).
That I know of, the best cooler for the 42RLE is the 14 row Setrab that Blaine installs with many of his builds. I never saw higher than 180* with the Setrab in desert temps and it was usually cooler. Very impressive. I'm using the Setrab cooler for something else now so that's why I'm trying to make the Derale work for the transmission.
I would have preferred to buy a 160* switch (from a third-party seller) so the fan would come on when the pan reads about 180*, but that wasn't available off the shelf so I purchased a 150* knowing I can have them make me a 160* switch later. We'll see what happens.
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Near as I can tell you’re frustrated that the news reports that it’s 72 at the airport but your a/c hasn’t kicked on despite your thermostat being set at 68.
Lots of factors could cause a several degree variance between what’s inside the trans & what the derale measures, and lots of factors will contribute to that not being a fixed amount. And yeah, the switch itself is going to have some sort of tolerance too. You could do a direct test of the switch. I mean, you haven’t proved anything that would cause Derale to respond, as far as I can tell.
But you have your plan, I’m not attempting to divert you from it. I just don’t think it’s particularly scientific. Godspeed.
edit: spelling
Lots of factors could cause a several degree variance between what’s inside the trans & what the derale measures, and lots of factors will contribute to that not being a fixed amount. And yeah, the switch itself is going to have some sort of tolerance too. You could do a direct test of the switch. I mean, you haven’t proved anything that would cause Derale to respond, as far as I can tell.
But you have your plan, I’m not attempting to divert you from it. I just don’t think it’s particularly scientific. Godspeed.
edit: spelling
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Might want to hit the brakes before you talk more out of turn.
I told Summit of my issue and they stated that it’s not running correctly for my application.
Yes, I explained when the switch turns on vs the temp reading in the pan. I have videos of the fan running in the 190s and videos of it not running at 205. I felt it would be wise to inquire about this rather than assume I’d be good and potentially end up damaging my transmission.
Yet in your eyes, I haven’t proven anything to cause Derale to respond to a paying customer with reasonable concerns.
Anyhow, I explained that I’d like to run a lower switch and summit agreed that doing so seemed like a good idea. They told me to contact Derale to get their advice and to see what their other switch options might me. I did so and never heard back.
Might want to hit the brakes before you talk more out of turn.
I told Summit of my issue and they stated that it’s not running correctly for my application.
Yes, I explained when the switch turns on vs the temp reading in the pan. I have videos of the fan running in the 190s and videos of it not running at 205. I felt it would be wise to inquire about this rather than assume I’d be good and potentially end up damaging my transmission.
Yet in your eyes, I haven’t proven anything to cause Derale to respond to a paying customer with reasonable concerns.
Anyhow, I explained that I’d like to run a lower switch and summit agreed that doing so seemed like a good idea. They told me to contact Derale to get their advice and to see what their other switch options might me. I did so and never heard back.
IIRC to stick with Derale products you need probe 16753 and the adjustable controller 16759? to be able to dial in a more specific on temp. The delta between on/off will still be 20*. You have to experiment to make the on setting coincide with the pan temps your seeing as it is a simple adjustment screw with no increments.
lol ok
You've got great data about the temperature at a different part of the transmission, and you know when the switch opens relative to that measured temperature. I have not seen where you measured the temperature at the Derale switch to prove that it turns on 20* late. Maybe you have that data, I don't think you've shared it here.Yes, I explained when the switch turns on vs the temp reading in the pan. I have videos of the fan running in the 190s and videos of it not running at 205. I felt it would be wise to inquire about this rather than assume I’d be good and potentially end up damaging my transmission.
Yet in your eyes, I haven’t proven anything to cause Derale to respond to a paying customer with reasonable concerns.
<unfollows thread>
Might want to hit the brakes before you talk more out of turn.
I told Summit of my issue and they stated that it’s not running correctly for my application.
Yes, I explained when the switch turns on vs the temp reading in the pan. I have videos of the fan running in the 190s and videos of it not running at 205. I felt it would be wise to inquire about this rather than assume I’d be good and potentially end up damaging my transmission.
Yet in your eyes, I haven’t proven anything to cause Derale to respond to a paying customer with reasonable concerns.
Anyhow, I explained that I’d like to run a lower switch and summit agreed that doing so seemed like a good idea. They told me to contact Derale to get their advice and to see what their other switch options might me. I did so and never heard back.
does the derale sensor go downstream of cooler, as the oil returns to the transmission? Or maybe between the radiator cooler and upstream of the derale cooler?
There's a lot going on between the PCM's sensor (I believe above the valve body) and the cooler lines, that not only makes them basically always different, but that their relationship likely isn't even consistent. Everything from engine speed, vehicle speed, hydraulic pressure, what gear you're in, whether you're coming down from a higher load or up from a lower load, and probably even current and preceding TCC lockup status all "turn a dial" influencing how much heat is moving around in that system and where it's going.
I think all hear is trying to say is that the switch not activating at a consistent internal trans temp does not mean it's not activating consistently for its own measured temperature and derale's failure to respond may be due to them deeming this as non-proof of there being a problem with their switch (other than possibly personal preference for a lower setpoint). Getting one with a lower setpoint may keep the temperatures where you want but it may not be worthwhile to hold your breath for one that you can see responding consistently to a temperature read from elsewhere in the system.
Tbh I’m keeping things simple because it doesn’t need to get complicated. All I care about is the temperature reported to the PCM by the NSS.
I’ve simply been looking for a lower-temp switch since the fan currently turns on 20* hotter than I want to see.
I called summit to see if there was a lower temp switch available. They couldn’t find one in their search so they advised me to contact Derale and agreed that I should get a temp switch that closes about 20* lower. I did as Summit suggested and Derale didn’t reply.
Thus, I ordered a lower temp switch with a 6-32 stud from a company in Wisconsin five or so days ago and should receive the switch soon.
Other folks have reported seeing pan temps with this kit around 220*. I hope to prevent my transmission from getting that hot once I’m off-roading with this cooler (which I haven’t done with this cooler yet). I prefer to not mess around on something like this and I think my decisions have been objectively reasonable.
Fwiw, Bullripper recently told me to not let the ATF+4 get to or exceed 220* bc the fluid loses viscosity and needs to be drained if that happens. All the more reason to pursue turning on the fan sooner and not assume Derale ignored my communications because it’s wise to run their kit as is.
In other words, Derale’s switch may function as designed yet not be the proper switch to adequately cool my the 42RLE. I’m doing my due diligence in hopes to improve the results.
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Other folks reported that their 42RLE pans also read about 200* when the fan turns on and their temps were higher when off-roading. This valuable info was not lost on me.
My priority is lowering the temps reported by the pan. I’ll be installing a lower temp switch soon and will evaluate the results.
To be clear, I don’t think the derale switch is bad. I think it’s rated to close at a temp that’s higher than i need for my application…and the variance in when it closes means that it’s not always closing when the temps reach as high as 205*. I prefer to avoid temps reaching 220* when under higher load, and imo installing a lower temp switch is a logical/practical troubleshooting step.
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I have had problems with my Derale switch also. My original derale cooler came with the wrong switch. I bought a replacement from e-trailer and that solved my issues. I am measuring my tranny temp at the pan (thanks to Blaine's help years ago). I rarely get above 190 and usually stay closer to 180. Measuring the temp at the pan fairly closely matches when the derale cooler kick on and off.
Derale system is designed to turn on when temperature of the ATF coming from the radiator is higher than 180F.
Has nothing to with pan temperature.
If the the pan temperature is 195 but the radiator cools the ATF down to 179F before returning to the pan, the inline Derale will do nothing, it does not see any overheat.
During my yesterday rise in the forest, the transmission was consistently between 185F to 195F. The fan was kicking in and out, mainly depending on the engine temperature. If the engine temperature was low, then the radiator will cools it down very well.
Has nothing to with pan temperature.
If the the pan temperature is 195 but the radiator cools the ATF down to 179F before returning to the pan, the inline Derale will do nothing, it does not see any overheat.
During my yesterday rise in the forest, the transmission was consistently between 185F to 195F. The fan was kicking in and out, mainly depending on the engine temperature. If the engine temperature was low, then the radiator will cools it down very well.
Who said otherwise? You’re making a point that’s pretty clear based on our shared observations. I only care what the temp is in the pan.
My pan is reporting 205.
205 is not a good number to be at in normal driving.
It appears you don’t have the issue I’m having. I’m constantly over 200* in normal driving….many times with the fan off (not ideal). It would likely be higher when off-roading that’s why I’ll be trying a lower temp switch.
I’m not interested in getting caught in the weeds regarding what the temps are at every step of the way. For my issue, I simply care to know what my temps are in the pan when the fan turns on.
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That’s interesting. I have a lower temp switch on order. I’ll get a higher temperature switch if what I purchased prices to be lower than ideal. That would be a good problem to have.
I've had similar issues with mine and understand what you're trying to accomplish.
However, I have yet to see the fan (turning on) have much of an impact.
I'll be curious to see whether the fan can reduce the temperatures by 20° from 150, like it's supposed to at 180.
This is interesting. I wonder if this is another case of the thinkdiag2 incorrectly decoding a value?
Oddly enough, the 20* number has been discussed for two different reasons.
1. The derale fan turns on when my aeroforce gauge reads 200* from NSS to the PCM, which is why I assumed the derale switch turns on around 180* (with variance) and simply isn’t the right switch for my needs.
2. Separately, when recording live TCM data recently, the thinkdiag2 provided a Celcius reading of about 225* when the aeroforce gauge reported the temp of about 205*.
I believed the thinkdiag2 was incorrect verified that its 225* reading was wrong by about 20* by hooking up my spare autometer temp gauge from the pan which read similar my aeroforce gauge and about 20* less than the incorrect reading from the thinkdiag2.
I hope that helps clear things up.
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