Has anyone bypassed the radiator in the transmission cooling loop? I'm referring to 2nd Gens, as I'm not sure if 3rd Gens were fitted with transmission coolers.

If you look down into the engine bay, you'll see two black hoses coming out of the transmission. One runs into the main engine radiator via a brass line, the other runs into a small external radiator mounted in front of the air conditioning condenser. What I'm thinking of doing is bypassing the main radiator, with copper line and some 3/8" I.D hose.

My main concern is transmission heat. Obviously the transmisson oil is directed to the main radiator for a purpose. The only reason I can think of is that it's to heat the transmission fluid, like a heat exchanger, but as the engine coolant warms to operating temperature, it'll only raise the temperature of the transmission fluid to match, right?

I'm not a transmission expert, but isn't overheating the main cause of failure for auto boxes?
Is cooler transmission fluid detrimental to transmission operation (ie. cold starts)?

I'll welcome anyone's input or suggestions :cool:

the heat of the radiator is generally the same as the recamended operating temp for the tranny. However. all tranny specialest recamend an external tranny cooler when towing or abusive behavior we be encounted.
haveing a tranny that heats up slower than the motor will result in harsh shifting when cold, but it will heat up. the cooler in rad helps it get to temp and stay at that temp, provided you dont cook ya motor.

It would be logical that it's there to cool the fluid?

Because of the tremendous heat generated in an automatic transmission, an auxiliary transmission oil cooler is an economical way to help protect against costly transmission repairs.

Automatic transmission fluid (ATF) cools, lubricates and cleans internal transmission components.When transmission temperatures exceed 93°C (200°F), the ability of ATF to perform is greatly diminished. Subsequently, the life span of the fluid, seal and moving parts are significantly reduced. Higher internal temperatures also increase the wear rate of the friction and clutch plates.



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Because of the tremendous heat generated in an automatic transmission, an auxiliary transmission oil cooler is an economical way to help protect against costly transmission repairs.

Automatic transmission fluid (ATF) cools, lubricates and cleans internal transmission components.When transmission temperatures exceed 93°C (200°F), the ability of ATF to perform is greatly diminished. Subsequently, the life span of the fluid, seal and moving parts are significantly reduced. Higher internal temperatures also increase the wear rate of the friction and clutch plates.



http://www.daviescraig.com.au/main/display.asp?pid=12

check out the site

thats what i was trying to say

Thanks for the replies guys, I guess that pretty much kills the idea I had in mind.

Ahh....look more carefully, the transmission fluid line does not go into the main radiator! It may look like it at first glance, but it isn't.

in my gen1, i have the best of both worlds... i plumbed the fluid so it goes into the radiator cooler, then into an external cooler then back to the trans.

TecoDan, the transmission line DOES go into the radiator, but not into the main coolant tank. There's a small tank, contained within the radiator, but sealed separately from it, which the line runs into.

BCX7, that's how my 2nd Gen is set up. How big is your external trans cooler?