stand-alone ux trans fluid cooler

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Apr 23, 2013
I'm installing a TH-350 in an old Chevy 1/2 ton pickup that doesn't have a trans cooler in the radiator. What are your thoughts on using only an auxiliary cooler, like a Hayden 678?

I live in north Texas where we don't see a lot of really cold weather, so I don't think I need to worry about getting the trans fluid up to temp. But I do want to keep it below 200F on 100 degree days. I doubt I'll ever pull a trailer or haul more than 1000 lbs.
A remote cooler is a great way to go, I can't help you with the ideal size for your application.
I run a tru cool 4590 trans cooler along with the in radiator cooler on my 78 chevy k20. I also have a transmission temp guage monitoring the output temp from the th400 transmission. This trans does not have a lockup torque converter. Im not sure if the th350 has a lockup converter. If it does that will cut down a little on transmission temps. I plow in the winter and the highest the temp has been is 210f. If i am driving on a hot day in city traffic it can get up to 180f. If i am cruising down the street it normally stays 160f or cooler. A thing to consider is that the external cooler is keeping the trans very cool while the in radiator cooler is trying to heat up the trans. My cooler is having to work harder that yours would because it has to shed the heat from the trans and the radiator. If you are going to run just an external cooler i would take a look at this offering from autozone It is a nice cooler for a nice price that can be picked up quickly in store. It does not get to hot here in ny but in texas i would go with the largest auxillary cooler i could fit. It may not be a bad idea to grab a trans temp guage if you are concerned about temps.
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The torque converter is pretty much why there is the oil cooler. Notice the oil to the cooler comes from the torque converter?
Thanks for all the info, guys!

Joe Green, where did you physically connect the temp gauge? By the way, great football career.
I connected it to the output from the trans. This is the highest temp the oil will see because it comes right from the torque converter. You can put it in the pan for an average temp but i like to see the max oil temp because i can get a much better idea of the oil temps throughout the rest of the system. I used the autometer cobalt trans temp guage.
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