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AW4 trans oil cooler question


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I am installing a cooler on my truck and I just wanted to verify which line I should use for the cooler. I think I am supposed to cut the top line going into the radiator and just run the cooler in line. Is this correct or should I use the bottom line?

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i did mine almost 2 years ago and have a foggy memory, but i believe i ran mine in line with the factory cooler in the radiator. so the bottom line if i rember right. i followed directons that came with my B&M cooler. you could always contact the manufacture and ask for a professional opnion

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I am installing a cooler on my truck and I just wanted to verify which line I should use for the cooler. I think I am supposed to cut the top line going into the radiator and just run the cooler in line. Is this correct or should I use the bottom line?

 

:huh???: Tranny oil coolers are always installed in series with the return line. Do your own research to ID if it's the upper or lower line on the radiator depending on whatever truck you're referring to. And/or if you want to keep the built-in radiator tranny oil cooler when you plumb it in.

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This is how the factory plumbs in the aux cooler and is the way I did mine. The cooler is in plumbed in series with the bottom radiator line which is the transmission return line. The transmission return line is always the rearmost cooling line on the AW4 transmission.

 

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I rigged mine inline but before the fluid enters the main rad.

The logic? Based on advice from "a mechanic" . . . . . . In the winter the trans fluid needs to be brought up to operating temperature.

 

The outside temp drops down to 10degreesF (-12C) occasionally around here or when I head up into the mountains so without going through the main rad after the trans cooler the atf will get too cold and may cause trouble.

 

The factory design keeps the trans fluid close to whatever temp the motor is running at.

 

Useful auto trans info - http://oldihc.org/automatic-transmission-cooling-2

 

Worth mentioning I think for anyone installing a cooler and bypassing the main radiator:

From link above

OVERCOOLING

In cold weather, excessive cooling can increase the fluid viscosity to a point where flow to vital transmission components is restricted. RVers who travel in both hot and cold weather may experience premature transmission trouble if they have installed a large auxiliary cooler.

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Thanks guys.. I saw several people say use the top line but my FSM says the factory is the bottom like hornbrod posted so I was confused. I guess I will use the bottom line seeing as how that makes the most sense for cooling purposes.

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