BMS Mission Oil Cooler ver.2

[Moonbastic]

I recently purchased and installed BMS Mission Oil Cooler ver.2.
After installing the above product, we check the mission oil temperature every day, and it is very hot summer in Korea. The average temperature is over 33 degrees, and even though the traffic is serious, it does not exceed 73 degrees.
It is maintained between 150.8 ℉ and 154.4 ℉ (66–68℃) when driving on the highway.
I know that the Mission Oil Thermostat opens between 186.8℉ and 190.4℉(86~88℃) degrees, and I know that 186.8℉ to 190.4℉(86~88℃) degrees is the best condition for mission operation, but I'm worried that it's too much cooling.
My country, Korea, is divided into four seasons. It is very hot in summer and very cold in winter.
Especially in winter, I'm already worried because I think the temperature will be difficult to exceed 60 degrees. I'd appreciate it if you could give me good advice based on your knowledge.

 

[oddball]

I assume "mission" is an autocorrect error for "transmission".

Engine oil needs to be above 180 degrees F to remove water, so the ideal operating range for engine oil is around 200 degrees F. Cooling engine oil too much can cause problems because water and other contaminants won't evaporate, and engine oil changes viscosity quite a lot in its temperature range. The contaminants come from combustion.

Transmission fluid is very different and has very different functions. The ideal transmission fluid temperature is around 140 to 160 degrees F. I would expect the transmission thermostat to be around 160, not 180, but I am not certain. Transmissions don't have contaminant problems like engines. The friction material and metal parts will wear, so those physical contaminants need to be removed by the filter. There isn't a significant concern about water or other contaminants that need to be removed via heat like engine oil. Transmission fluid is also very thin and doesn't change viscosity as much as engine oil.

The temperature you are reading can vary quite a lot depending on where the sensor is located. If that is in the return line from the cooler then you would expect it to be less than the thermostat. If the sensor is in the pan or on the internal wiring harness then it will show the most useful reading.

Almost ALL of the heat for a transmission comes from the torque converter. That means driving in the city or stopped in gear is when the transmission heats up. Strong acceleration will generate a lot of heat quickly because the torque converter is managing a lot of power transfer changes. That's why racing on a track can generate a lot of heat, and in that case the fluid can exceed its rating - usually around 300 degrees F - and degrade.
The transmission develops very little heat when the lockup converter is engaged. I've seen transmission temperatures in other cars lower by over 30 degrees F when driving steadily on the highway.


The most important thing: Over-cooling a transmission really isn't a problem, unlike engine oil. And since there is already a thermostat there is no need to worry.

 

[djerickd]

good explaination