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Ok from what i understand on a TH-350 trans with an auxiliary and radiator cooler, the cooler line on bottom trans fitting goes into the bottom of the radiator cooler, then the cooler line on top goes into top of the auxiliary cooler then a line goes from bottom of auxiliary cooler to top of radiator cooler right?
 

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For the small amount of time the fluid is actually in the exchanger of the radiator it shouldn't matter which way it flows.

After looking briefly at two factory set-ups the top line from the trans goes to the top fitting of the radiator tank.

If adding an external cooler the flow should be through the radiator exchanger, and then through it and back to the transmission.
 

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Hate to dissagree M&M, but I understand it should be the other way.................1st through the rad cooler, then through the auxillary cooler. The theory is that the auxillary cooler works better, and that the rad cooler would heat it up again.

What is your theory for the other way around?
 

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I always hook up the aux cooler before the radiator cooler. This keeps the trans fluid closer to the correct operating temp. As the radiator mounted cooler warms up the cold fluid faster, then sends it back to the trans at closer to the correct temp under operating conditions. The trans cooler in the return line would tend to overcool the trans fluid. A lot of modern overdrive transmissions require the fluid HOT (but not overhot) to operate correctly.
 

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For street use, I was alway told you wanted to warm the fluid back up in the radiator exchanger so it wouldn't go into the tranny "thick" in very cold weather.
 

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Either way you hook it up, the end result is going to be nearly the same when you have all other variable conditions (trans fluid temp, engine coolant temp, and ambient air temp) remaining the same.

Winter temperatures can have just as detrimental a result of cooling the fluid too much, as overheating the fluid.
 

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Novaman78 said:
Ok so i can hook it up like this?
hooking up the directions pictured is fine.

I have never seen much difference in the oppisite direction.

Liquid to liquid heat exchangers are generally more efficent than air to liquid
 

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EVERY factory auxilary cooler is secondary to the water (heat exchanger) cooler. Go find a truck with factory towing package,or better yet take a close look at the image posted in this thread. The manufacturer wants the trans temp to be close to engine temp. The oil will reach operating temp fastest if routed thru the radiator FIRST.
Most aux. coolers have thermal bypass now to limit their operation until the fluid is warm.

Remember this when working on your back...replacing a modern trans without replacing the cooler is certain death. :nono:
 

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If you haven't already bought your trans cooler, I would strongly suggest the Long Tru Cool LPD (low pressure drop) coolers. They are a very effective stacked plate design and come in several sizes. Most of the larger ones have a thermal bypass built in, and I think all of them come with metal mounting brackets (not the zip ties used on cheaper coolers).

Bruce
 

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If your radiator is running a constant temp, your feed is always into the top of the radiator, out the bottom, then into your extra cooler, and then into the transmission. Your fluid temp is one temp, once it hits the radiator, it will be the same temp as the water in the radiator when it leaves the radiator. Your external will cool it down even more so before the return to the transmission. So to even make it cooler, and you want that extra fluid cooler on your ride, mount it in front of the radiator and add a pusher fan to to the cooler. Then your fluid will be near close to the ambient temperature when returning to the transmission. The reason for the pusher fan, when in city driving, you are not moving fast enough to have the full effect of the external cooler. The fan is actuated by a solenoid sensor separate from the water temp control sensor. Good luck.
 
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