Automatic transmission cooler question

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Dave M

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My pickup runs a TH400 trans and I was wanting to fit a trans cooler to it. I can get a factory GM one suited for a 460LE auto, they're cheap and in abundance at any wreckers. Would one of these be big enough and sized right for the TH400.
 

Rusty Nail

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Yep.
Damned near ANY size would prove beneficial I reckon but i'm also betting that bigger is better.

In a side note, when I built a drag racing car I installed the biggest mother I could find cheap and it is rated for a 24,000 GVW capacity vehicle. (semi truck)
In comparasion, the parts store computer lists a 12,000? GVW cooler for a K5 and it is almost exactly HALF THE SIZE.

I can ALSO ADD the transmission shop that sold me a rebuilt transmission WARRANTY demanded a cooler be installed yet....they did NOT utilize the factory cooler in the brand new radiator , they only hooked up the aftermarket $40 Perma-Cool unit that is installed behind the grille...and warrantied it like that!
I wanted that additional capacity though because
I thought more is better?

Good luck.
Hope this helps!
 
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ali_c20

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Go for it.
 

75gmck25

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The most effective coolers are stacked plate design like the Long Mfg. Tru-Cool Low Pressure Drop (LPD) coolers. I believe the B&M coolers are rebadged Long coolers. You can get Long coolers with GVW ratings up to about 28,000 lbs. Most come with metal mounting plates, not the cheap push-through plastic retainers.

Bruce
 
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Ricko1966

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Transmission fluid just like motor oil works best at certain temperatures to hot is bad, too cold is bad also.Thats why so many manufacturers use the radiator as a transmission cooler, the fluid stays a relatively constant temperature and the fluid warms up way faster in the winter because the radiator is actually heating it.If you want to add a cooler I'd add it before the factory cooler to keep the temperature regulating feature.
 

Matt69olds

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Any cooler is better than none. As someone mentioned before, it is possible to overcool a trans. With a non lockup converter like what’s in a 400, it would be very difficult to overcool a non lock up trans.

If you look at the cooler flow diagram of a 700/4L60, you will see the cooler flow is restricted while the converter is locked. That’s so when your driving on the interstate with the outside temp -10 below zero, the trans doesn’t get too cold. Most of the heat in a transmission comes from the torque converter.

Ok, transmission cooler lesson is over, class dismissed!

Install a cooler, keep the radiator cooler also. If you plumb the auxiliary cooler ahead of the radiator cooler, then the radiator cooler will keep the trans from getting too cool. It might also help the cooling system if the engine normally runs warmer than desired. On the flip side, if you really work the truck in the heat, at low speeds, then the cooler after the radiator would probably be best. That way, the auxiliary cooler can radiate extra heat before it gets back to the trans.


Lastly, if you don’t already have one, a deep pan is a big help. The deep pans hold an extra 3 quarts (I think) and are a simple bolt on. The factory deep pan needs to longer filter tube, longer filter bolt and extension sleeve. Aftermarket deep pans will include everything needed to install.
 

75gmck25

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The Long Tru-Cool transmission coolers have a thermal bypass built in, and it lets the fluid bypass the aux cooler if the fluid temp is below 180 degrees. They recommend installing the cooler after the in-radiator cooler.

Bruce
 

austinado16

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I installed the big 11"x11" Long Tru-Cool/B&M Supercooler. Yes, it needs to be installed after the heat exchanger that's in the radiator. Yes it has a passive bypass that keeps the oil from circulating through the entire thing, until the oil gets hot and thins out. Lastly, pay attention to how you mount it, and where your hoses are for inlet and outlet. It needs to have the fittings facing either sideways, or up. If they face down, it will not fill itself with oil, and will just function in bypass mode. I found this out the hard way.

I added the 454 pusher fan in front of mine, and switch below the dash, that allows my to run the fan as needed for a boost in cooling.

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