Moparts Tech Archive

Automatic Trans.

Trans coolers...how big is too big?

I've heard of guys running a smaller AC condenser as an Auto trans cooler...seems kind of big to me...any thoughts? Can the trans fluid get too cool?

actually, yes. you want it to be around 180' for everything to work right. using a cooler as big as a AC condenser just blocks the air from properly cooling the engine, so i don't know where they're headed... if you want to stay cool, get a MP deep trans pan (get the non-chrome one, as chrome actually retains heat, and spray it with a good engine paint either silver or the color of your trans), an external cooler (summit pn SUM-G4960) (run the fluid through the regular radiator cooler first, then through the external cooler, and then back to the trans), and a poly graphite trans mount (summit stockes them). also, run type "f" fluid. you know those fancy-pants trans fluids you see? they're plain old type F. just so you know for the cooler, on a 727 the fitting closest to the front of the car is the supply, and the one to the rear is the return.

i personally like the biggest plated cooler you can put on. much better than the tube types. i use the b&m super cooler but others make them as well. i would rather be to cool than to hot!! i also run mobil 1 synthetic fliud.

Nice thing about the plate type is they usually have both connections tapped for pipe nipples. Don't forget to have the return line on the top to prevent gravity draining.

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How do you all feel about by-passing the radiator all together? I have a medium to large size cooler mounted to the front of the trans. I will also be running Amsoil Synthectic trans fluid. 440/727/3500 stall

ok, let's try this again. your engine and trans should run just around 180. by running the fluid through the stock cooler first, it will take it back down to engine temp (180). also, it will be cooled further by then going into the external cooler, which should be hit by the cold air first, making the fluid even cooler before getting back to the trans. that's the whole reason of adding an extra cooler - you're cooling the fluid IN ADDITION to the powerful cooling properties of the stock cooler. also, when you are moving at a slow speed or stopped, you are assured that the trans will still be cooled sufficiently. you are better off to run both.

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