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Discussion Starter · #1 ·
Right now the tranny cooler fan is wired to be always on but this isn't really optimal, especially in the winter on a cold start.

Has anyone wired their tranny cooler fan to the wiring for the stock fan in front of the radiator on a auto that is removed when you install an fmic? I'm just wondering if the temperature that it switches on will be appropriate for the temperature that the tranny oil needs to be.
 

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I wired my tranny cooler fan like that. It will switch on only when the A/C is on and when the temp rise to a specific figure. So far the highest temp i see on my tranny is about 230 deg F. I set warning at 212 Is that too high?

I am planning to make a separate switch for the fan so i can switch it on and off anytime.
 

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Discussion Starter · #3 · (Edited)
Do you know at what temp the fan switches on? Around what temp is yours at most of the time?

The tranny temps should usually be around 160 but I think as long as it averages below 200 most of the time it should be ok.

There are some fan/cooler combos on summitracing that have 160 degree thermostats built in. I was thinking of just getting on of those if wiring it this way would make the temp too high.
 

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I would suggest having it wired to come on as soon as you start your car. This seems to help cooling. IMO, I would consider it kind of like when your car in on the dyno. You don't wait till the car/FMIC is heat-soaked before you turn on the fan, do you? As long as you perform a normal warm-up of you car (you don't just start your car cold and drive off at WOT) your tranny fluid temps should be warm enough to avoid issues.

BTW, for the person seeing peak 230 temps, that is high and you might want to check/change your fluid when you hit those temps. From my reading/research, goal should be to keep it under 200 F and would set your warning indicator accordingly. That would be ~95C for those with gauges in degrees C. Once you cross over 200 F with regularity is when heat appears to really starts impacting fluid/tranny/TC life.

Brad
 

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Discussion Starter · #6 ·
I figured it's probably taking a while to warm up when it's idling in freezing temperatures in the winter. I'm not sure how long tranny fluid takes to warm up but engine oil probably takes at least 10 minutes of driving to warm up to full temp.
 

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The stock themo switch on the fan at 98 deg C

Brad is right about temp over 200F. If the temp goes up to over 200F frequently its recommended to do a regular tranny oil change say every 5000 - 10000 miles

I found a write up about this so and i use it as a guide for oil change

-----------------------------------Quote-------------------------------
Automatic transmission fluid will provide 100,000 miles of service before oxidation occurs under normal operating temperatures of about 170°F. Above normal operating temperatures, the oxidation rate doubles (useful life of fluid is cut in half) with each 20° increase in temperature.
The approximate life expectancy at various temperatures is as follows:
175°F 100,000 miles
195°F 50,000 miles
212°F 25,000 miles
235°F 12,000 miles
255°F 6,250 miles
275°F 3,000 miles
295°F 1,500 miles
315°F 750 miles
335°F 325 miles
355°F 160 miles
375°F 80 miles
390°F 40 miles
415°F Less than 30 minutes
This information clearly shows why transmission oil coolers and the various maintenance intervals are recommended for severe usage.
Above 300°F, the metals inside the transmission will warp and distort in varying degrees depending on the severity of overheat. Because this damage occurs and fluid life is so seriously impaired, rocking out of snow, mud or sand should never exceed a very few minutes.
--------------------------------------------------------------end--------------------------------------

Hope this will help you in your quest ;-)
 

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supra8388 said:
horsepower
Not entirely true... you can be stock, put in a high stall, and you will see higher temperatures. It's the slippage of the converter and other factors.
 

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Ok you are right, the slippage is a factor, therefore when its locked at high rpm, you will see that the temp slowly dropping back to 80C. Generally the amount of torque + slippage, the higher this combo is, the more heat, just to make it simple.
 
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