Transimission Heat Issues on Gen V trans and TCC explanation needed

I have a 68 Camaro with a L86/10l80 trans and I just started driving it more and the first long drive I higher than normal temps around 195 degrees before I got home. This temp could have kept going up but it held strong and only dropped around 1 degree, other than that it just kept increasing over a 30 min drive of stop and go and longer 50mph roads. I know this temp is not too high but I dont know where it will eventually stop and I don't want it to be an issue while I'm out and about. My wifes 2018 with the same motor and trans is hard to get to 180 degrees and drops down to the 160-170 range once it gets that high. Also on these newer transmissions I think they have a temp controled pump so it doesnt turn on until a desired temp but I do not know the temp.

The car has a swap harness and the way its wired is different from other swap harness builders like Speartech. The harness has a brake wire that is to see 12v when brakes are applied but other harness builders want to see 12v when brakes are depressed. I'm wondering if the converter is doing something strange and causing heat to build up. The harness builder said this is just how he sets them up and he has tested it and the TCC receives its needed signal either way, pressed or depressed. VCM scanner shows brake applied when the pedal is pressed so I'm assuming its working correctly? To help troubleshoot this I'd like to know if someone could explane the TCC function on the newer transmissions, mine in particular and tell me what PIDs to log and check for? Only PIDs I'm seeing are the TCC line pressure, TCC slip, TCC desired slip and they read in RPMs the converter isnt just locked or unlocked like older transmissions.

I believe my radiator is sufficient to cool the trans but I'd like to explore the TCC first.

Another issue is the trans just threw a bunch of solenoid out of calibration codes and this could have caused this heat issue too. These were not present prior to this. I tired to clear them but they came back. I tried a fast learn and it aborted each time I started it. Other then the codes it drives like it did before.

I know its a lot to take in but any help will be greatly appreciated, thanks!

Curious question, do those transmission run a cooler line thermostat like some of the older 6 speed auto did?

The 8 speed has a thermostat and thermostat problems. I saw one get hot enough to melt last year in a race truck... Not sure about the 10 speed. Your wife's 18 has an additional cooler joined with the AC condenser so that has to play a big role. If your only cooler is in the radiator and the antifreeze is 195+... I am curious if it would have continued over 200 or stabilized near coolant temp.

I think that our standards for ATF temps are changing the days. Starting with the 8 speed they say we can't run Dex6 anymore because while it is chemically compatible with the HP8 stuff it cannot handle the heat that the 8 speed throws at it. I don't tow much anymore so I don't really keep an eye on it.

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Originally Posted by 5FDP

Curious question, do those transmission run a cooler line thermostat like some of the older 6 speed auto did?

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Yes I believe it has a thermostat but not sure what temp it opens.

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Originally Posted by IARLLC

The 8 speed has a thermostat and thermostat problems. I saw one get hot enough to melt last year in a race truck... Not sure about the 10 speed. Your wife's 18 has an additional cooler joined with the AC condenser so that has to play a big role. If your only cooler is in the radiator and the antifreeze is 195+... I am curious if it would have continued over 200 or stabilized near coolant temp.

I think that our standards for ATF temps are changing the days. Starting with the 8 speed they say we can't run Dex6 anymore because while it is chemically compatible with the HP8 stuff it cannot handle the heat that the 8 speed throws at it. I don't tow much anymore so I don't really keep an eye on it.

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Not too sure what my wifes car has going on for the cooler. Earlier today I double checked I had the inlet and outlet cooler lines ran correctly according to her setup. I did notice the inlet is at the top of the rad and the outlet is on the opposite corner of the rad, not sure if it went to another cooler or not and shes gone at the moment.

Yea, with the thermostat it is kind of silly to think it opens to cool the trans but it runs it next to the hot engine coolant but should work if theres another cooler like you mentioned. I have also heard of the pump not working or the thermostat not working and causing 250+ degree temps. I think it might eventually stop heating up but its a concern for sure if I'm out and about.

Update: I did some digging and the gen 4s and 5s use the same 12v as the brake lights so I'm wired up correctly, the gen 3 and below use 12v when brakes are not applied.

So my wifes car (10 speed) and brothers truck (8 speed) both have large coolers in front of the radiator. The 8 speeds have a thermostat built in the cooler manifold but not sure where the 10 speeds have their thermostat if they even use one, anyone know? My 10 speed and wifes both do not have the thermostat int he cooler manifold like the 8 speeds do.

I may be experiencing high temps from either the thermostat being an issue if I have one or the small radiator and coolant temp affecting the cooling rate like mentioned above.

See link below for a video showing how to delete the thermostat on the 8 speeds. I would like to do this on my 10 speed but my manifold does not have previsions fo this mod.
https://www.youtube.com/watch?v=RmOg0rZlNLY&t=29s

Can you tell me who did your swap harness? I just picked up a 2019 L86 and 10l80 I want to stuff in my 51 Chevy truck. I picked up the combo before i researched all the things I need to do to get this particular combo working as a stand alone installation.