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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Thanks for your insight on this. I am using the 93 Service manual for info for the 42RH. According to it the operating temperature is 180F. So I’m wondering what is the fluid temperature is when leaving the radiator cooler? Is it radiator (or higher) temperature and by the time it gets back to the transmission has dropped back to near operating temp? Or if the external cooler receives it last at near radiator temperature, does it cool it to near operating temperature? I can’t find any more info in the service manual. I would be interested in finding out either way of doing it. I suppose i could do it one way or the other and mount my Dakota Digital trans temp sensor after one or the either final cooler. and then swap to after the other cooler, but that’s definitely a lot of work (and money for tubing!).