ATF Temperature

[Mark 4]

Does anyone know what the ideal operating temperature is for the ATF ?

[stuartturbo]

I would guess the same as the water as it run through the rad

[Davezj]

i am about to fit my auto trans temp sensor in the next couple of weeks so if you can wait that long i can give you the actual figures as long as it is above 80 deg C that is as the gauge starts at 80 and goes to 150.
i would have thought if the oil cooler in the radiator is to cool the ATF running through it then the ATF will be running at above 100 Deg C ish. as i would have thought the radiator water would be about that temp. i know the pressure in the cooling system and the anti freeze itself will raise the point at which the water will boil, but not stop it boiling. So if the rad temp went too high above normal boiling point of water then evrything would start going tits up and water would boil out of the expansion tank and probably crack either the rad or pipes. my point is the ATF would have to be hotter than this to get any kind of cooling effect from the rad mounted cooler, and as the ATF is not in the cooler for a long period of time then the temp difference would have to be larger for this cooler to work properly.

Before anyone else says it yes i know the cooler in the rad acts as a heater as well to bring the ATF to working temp quicker as the water in the rad heats up much quicker than the ATF oil would normally heat up if it did not flow through the rad cooler at all. if that makes any sense. so the rad cooler actuall maintains the temp of the ATF if it is under temp or over temp.

[Mark 4]

Got that Dave. Please let me know when you know more. Thanks.