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Why do automatic tranny cooler lines run through the radiator?

Slide

By Slide,
in Engines & Forced Induction

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Slide Grand Master

Slide

Posted
Posted

Why do automatic tranny cooler lines run through the radiator?

Thats the question.

Do only autos come with the radiator that ducts them in?

Can i bypass it and run just a front mount AT oil cooler or does it assist in the cooling or oil thining/thickening?

Cheers

oil_cooler.JPG

SteveL Mentor

SteveL

Posted
Posted
Why do automatic tranny cooler lines run through the radiator?

Thats the question.

Do only autos come with the radiator that ducts them in?

Can i bypass it and run just a front mount AT oil cooler or does it assist in the cooling or oil thining/thickening?

It's an oil cooler and generally all auto cars have one in the radiator. Yes you can run a separate trans oil cooler - it actually extends the life of the tranny esp if you plan on engine power boosts.

Slide Grand Master

Slide

Posted
  • Author
Posted

I know its an oil cooler the point of the question is why is it ducted into the radiator

and what ramifications will it have if not used but just running a big tranny oil cooler

Cheers

SteveL Mentor

SteveL

Posted
Posted
I know its an oil cooler the point of the question is why is it ducted into the radiator

and what ramifications will it have if not used but just running a big tranny oil cooler

Cheers

It's cheaper to do it that way in mass production, plus it allows the tranny fluid to reach operating temp quicker which aids driveability. I've also read somewhere of one manufacturer (toyota from memory) claiming that it reduced emissions by optimising operating temps, etc.

It is almost invariably better to disconnect the factory cooler and run a separate air/oil trans cooler. The factory type is small and you can usually fit a larger aftermarket type that gives better cooling all round and will extend trans life. For a standard car the factory cooler will do the job, but boosting engine power or continuous engine load (eg towing) makes fitting an aftermarket cooler mandatory AFAIC.

Downsides - finding the space + the trans will take longer to reach operating temp esp in cold climates (eg winter in melbourne)

someonestolecc Grand Master

someonestolecc

Posted
Posted

I know for a fact there are atleast 2 different radiators for r32s. One is an auto one, with the trans cooler part, one is a manual one without it. Obviously I'm not 100% if *all* auto ones got the auto radiator or if *all* manual ones got the manual radiator but it would stand to reason.

Cubes Grand Master

Cubes

Posted
Posted

I would probably keep the transfluid running in to the radiator then in to the external trans cooler then back to the gearbox.

Setup that way would no doubt help absorb peak hour traffic trans fluid temps when there is no air passing through the external trans cooler.

WazR32GTSt Grand Master

WazR32GTSt

Posted
Posted

when i fitted a trannie cooler to my R32 auto, i found that it did indeed have the factory AT oil cooler on the bottom of the radiator...

i simply run the fluid through this cooler, then through my aftermarket cooler, then back to the trannie :rofl:

Slide Grand Master

Slide

Posted
  • Author
Posted

How would running the AT cooler lines through the radiator assist in keeping the fluid cool?

Granted it getsit to operatin temp quicker but is this one of those things that pulls both ways?

I will be replacing my radiator with a manual one so i wont be running through the radiator but will the setup be okay still?

Abo Bob Grand Master

Abo Bob

Posted
Posted

You don't want your fluid too cold, it doesn't behave properly. They make these fluids to behave in a certain way in a certain temperature range. Outside the range and they don't work properly. I run mine through both the radiator and the cooler in the front drivers side air dam.

Sydneykid Grand Master

Sydneykid

Posted
Posted

The liquid (transmission fluid) to liguid (water in radiator) cooler is the most efficient. Liquid (transmission fluid) to air transmission cooler is not as efficient, so it has to be larger. The Stagea (have a look at the transmission cooler thread in the Stagea section) has both standard, I simply replaced the small standard air to fluid cooler with a much larger and more efficient Davies Crag transmisson cooler. But I kept the fluid to fluid cooler as well, can't have too much transmission cooling when towing.

As long as you use a large enough air to fluid transmssion cooler, then you can live without the fluid to fluid cooler. Make sure you put it in the line of airflow from the radiator fan, that will helpo when in traffic, not moving much for long periods.

:)

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