65 Dart Wagon Conversion to a Sedan Delivery

mpgmike said

I agree with you and disagree with the "transmission expert" on how to mount the cooler. Like engines, automatic transmissions have an operating temperature range. If you run to the external cooler first, you could cool the fluid below normal operating temperature. When the fluid goes to the radiator, it would be heated back up. Fluid back to the trans is at operating temperature. If you do it the way the 'expert' recommends, your transmission could spend most of its time below normal operating temperature, with possible reliability issues.

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Guess it depends on where you live and the ambient air temperature. It's always hot in SoFlo, so we run the external transmission cooler after the radiator transmission cooler for maximum cooling.

If we ran to the external cooler first, it would cool the tranny fluid, and then the radiator tranny cooler would re-heat the fluid after, and that would defeat the purpose of the external cooler. So might as well not run an external fluid cooler in a hot weather scenario; the external cooler needs to be downstream of the radiator cooler.

What ambient air temperature will you be driving in? Best bet is to use a thermostat bypass as someone else said, if you have extremes in hot and cold weather. However, I would say that if your ambient air temp will always be above 60*, I wouldn't worry about over cooling the tranny fluid and using a thermostatic bypass.