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How hot is too hot for auto tranny?

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Old 06-21-2003, 01:30 PM
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Default How hot is too hot for auto tranny?

My transmission shifts at a higher rpm when cold. In an effort to briing this temperature up a little quicker at the track I have bypassed my tranny cooler. With the cooler inline my temperature ran about 180 degrees after a pass with the engine at normal operating temperature before the run. I have not made a track pass but on the street now with the cooler bypassed it runs about 190 after a couple full throttle runs. May even get higher should I make multiple passes. I don't know for sure yet how much hotter it will run.

My question, is 190-200 too hot? What is an ideal temperature?
Old 06-21-2003, 01:57 PM
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Default Re: How hot is too hot for auto tranny?

It is supposed to shift like that when cold, dunno why just GM programmed the PCM to do that.

Anything over 175* is getting sorta hot, my truck with the factory cooler hits around 155* via AutoTap and a 195* thermostat. That temp worries me and is why I will install a bigger cooler (7"x14") inline with the stocker.

Now, engine oil temp needs to be around the high 180's from what I remember.
Old 06-21-2003, 03:43 PM
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Default Re: How hot is too hot for auto tranny?

At 226 degrees, the trans will go into "limp mode", converter will unlock, makes a lot of growling noises. Not good. Been there, done that.
Keep the cooler hooked up.
Old 06-21-2003, 04:26 PM
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Default Re: How hot is too hot for auto tranny?

That's weird, my tranny short shifts when it's cold.

Jeffrey
Old 06-21-2003, 07:52 PM
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Default Re: How hot is too hot for auto tranny?

I stop racing when the temp hits 200. I like 160 - 180 as my operating range.
Old 06-21-2003, 08:39 PM
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Default Re: How hot is too hot for auto tranny?

Thanks guys! Guess I better hook that cooler back up.

The cooler lines to the radiator run to the hot side (return side) of the radiator. Why didn't the factory run those line to the cool side so the tranny would run cooler? Maybe it will last longer in the 180 range. This is what it run in normal driving. Very close to engine temperature.

Old 06-27-2003, 11:54 AM
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Default Re: How hot is too hot for auto tranny?

Are all you guys Auto Tapping or is there a way to gauge temp otherwise?
Old 06-27-2003, 12:14 PM
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Default Re: How hot is too hot for auto tranny?

My trans temp....with a Vig3600 converter stays at 180 with temp gauge and trans cooler
Old 06-27-2003, 07:42 PM
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Default Re: How hot is too hot for auto tranny?

ShadowlightCSU,

I use Auto Tap to read my temps and everything else.

99PTA,

A PI 3600 is what I have. I have hooked my cooler back up but have not taken any readings with my current set up. I tried with the cooler under the car without the fans and it ran almost as hot as no cooler in traffic. I have the cooler where the fans will draw across it now.



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