Cooler Installation Kit? NOW WITH POLL.

Best Transmission Cooler Setup?

  • Cooler in radiator (stock)

    Votes: 0 0.0%
  • Added cooler without bypass thermostat (OEM TSB setup); transmission > radiator > cooler > transm.

    Votes: 7 41.2%
  • Added cooler with bypass thermostat; transmission > radiator > cooler > transmission

    Votes: 0 0.0%
  • Cooler only, without bypass thermostat; transmission > cooler > transmission

    Votes: 9 52.9%
  • Cooler only, with bypass thermostat; transmission > cooler > transmission

    Votes: 1 5.9%

  • Total voters
    17
The condenser doesnt always operate and when it does, temps should be 15-30 degrees above ambient. The transmission cooler a little over that, and the radiator being the hottest.

The radiator fan increases the air flow rate through the stack; so a sandwiched Trans cooler or cooler mounted directly to the condenser would benefit from the airflow when the vehicle is moving slower / stopped as opposed to a remote mounted cooler that relies on air flow alone. 🤔

But could it negatively impact the radiator, i.e., coolant getting hotter overall?

Case in point, certain years Panthers are actually like that, with the transmission cooler sandwiched between condenser and radiator. I can't say the exact year range, but after they eliminated the in-radiator cooler and before they combined condenser and transmission cooler in one. So roughly 2003-2005.
 
For radiate cooling painting it black is the best thing, for conduction and convection bare is better. Personally I'd say a light coat of paint to stop any oxidation from forming, the paint is more conductive than aluminum oxide.
 
Ok...so a little update.

I'm going through with my plan to connect to the lines just forward of the engine. To get in, I have to cut off these crimps:

20250827_140739.jpg

Pictured is a junkyard unit I got for training purposes. It's tedious; it requires a calm hand with a dremel. What comes out is a 5/16 line with a barb.

From there on, I want a single piece of hose per direction of flow. No adapters, just a neat installation with minimal failure points.
Ergo, I need a cooler with 5/16 connections. In the OEM sphere, that could be an E-150 cooler; however, junkyard units are all filthy, and new ones are pricey. In the aftermarket, all I can find at local stores is 3/8; however, there are 5/16 options online. Which brings me to my next question: is there anything wrong with a cheap Chinese made cooler? I mean it's just an aluminum tube really... This one is on Ebay for $22 with free shipping:

s-l1200-2.webp

They offer a smaller 6-row version, too:

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And another side note: I was wondering if the cooler could be detrimental to air flow and thereby make the radiator run hotter...

But then I thought the opposite must be true: since I'm planning to bypass the in-radiator transmission cooler altogether, the coolant should be cooler because it's no longer flowing past hot ATF.

Any thoughts on that cooler I posted above? I'm leaning toward the smaller 6-row version.
 
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A black anodized cooler cools best. The difference between bare and anodized is large at high temps.
 
Well, my Hayden 679 cooler should be delivered today. It's approximately 11"×11", stacked plate type. Meanwhile, I concocted a support based on the measurements from hyco bars and recycled junkyard hardware. The cooler will sit with the nozzles facing the driver side, because it's somewhat easier to route hoses that way. The V6 has the power steering cooler on the passenger side; plus I didn't want to clutter the area around the radiator drain; plus the transmission hardlines already point somewhat toward the driver side.

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On that type of cooler, aren't the supply/return fittings supposed to face the bottom?
Also, that strut on the left really should attach to both the top and bottom like the 1 on the right. If you can mount it on rubber that would be ideal. Just imho
 
On that type of cooler, aren't the supply/return fittings supposed to face the bottom?

From my reading, sideways is ideal to prevent air pockets, with ATF entering through the bottom nozzle.

Also, that strut on the left really should attach to both the top and bottom like the 1 on the right.

Agreed, but the left bottom sheet metal doesn't have that same hole/flat area to insert one of those sheet metal screw hole tabs I'm using in the other three corners. Even still, it sits very secure. I was considering limiting fore/aft movement in that corner with a strap from the bumper instead.
I mean Hayden suggests to install this thing using zip ties. I'm definitely making an effort...

If you can mount it on rubber that would be ideal. Just imho

:unsure: You think it gets too much vibration mounted firmly like this? I wasn't considering that... Now I remember that the radiator and condenser are mounted on rubber. Is that a serious concern? I don't really want to revisit the whole installation...
 
Agreed, but the left bottom sheet metal doesn't have that same hole/flat area to insert one of those sheet metal screw hole tabs I'm using in the other three corners. Even still, it sits very secure. I was considering limiting fore/aft movement in that corner with a strap from the bumper instead.
I mean Hayden suggests to install this thing using zip ties. I'm definitely making an effort
You can make a small angle bracket out of a piece of angle iron & drill 2 holes in it and bolt it in.

I always try to mount any type of radiator/cooler in rubber. But it's your car, you can mount it however you want.
With the rubber lines you'll probably be fine. All it would take is some rubber washers on your mounting brackets but that might be overkill for your application.
 
Didn't get much further today as the roommates summoned me for yard work.

I did install a second full length support bar. Thanks, @massacre :

20250830_180622.jpg

Meanwhile, I took another look at the cooler and realized it's slightly warped. It didn't seem used to me (though the box was unsealed). Also, there was no sign of fluid whatsoever. Is this just the usual quality? Or is this an issue? I'd hate to delay installation beyond tomorrow...

20250830_185426.jpg
 
Alright, car is back in one piece. Test drive with temperature checks tomorrow.

I must say, this is an involved modification, at least if you have a talent for making things more complicated.

I ended up securing the cooler with Christmas tree fasteners over foam (the foam was actually part of the kit). It sits very securely, but it still has some mild vibration absorption.

20250831_074739.jpg20250831_074712.jpg20250831_074726.jpg

On to the plumbing portion, I understand now why some people prefer to use steel lines. Running the rubber transmission lines  neatly is difficult. I did as best as I could, covered most of the lines in plastic casing (the type otherwise used for wiring), and ran everything via the driver side and underneath the washer reservoir.

After cutting the old lines initially, I was surprised how little fluid came out. It started flowing once I unscrewed the couplings from the radiator, but it ended up just half a cup. I filled up with one cup of fresh fluid, given the larger size of the cooler and longer new hoses.

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Getting the old hoses off these fittings was a pain!

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Finally, I plugged up the radiator, just in case I ever want to go back. Doubtful though, because my radiator is likely original. It has an extremely slow leak. I intend to keep it for as long as it'll do, especially now that it's separated from the transmission.

20250831_124812.jpg

As stated previously, the transmission doesn't get terribly hot in steady traffic in the 50-60 mph range. However, cruising at 70+ mph or any sort of local stop and go traffic, the transmission matches engine temperature or briefly exceeds it. I would be satisfied if this new cooler consistently kept the transmission 30°F lower. Why 30? No idea, but it feels right.
 
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First drive today. Not a comprehensive test, as I don't really have anywhere to go. Just local errands, multiple short drives totaling about 25 miles, including one brief freeway segment toward the end. Temperature topped out at 133°F; from experience I can say that's about 20°F lower than what I would usually see on such a short trip after a cold start. It's promising, but the real test will be long distance freeway and longer/multiple city trips throughout the day (non-cold starts).

Apart from measurable improvements, I must say that it gives me peace of mind that I'll never see strawberry milkshake in my transmission!

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IME I usually see trans temps top out about 90-100F above ambient, depending on speed and temps. It doesn't usually get much above 90F around here, so I rarely see a TOT over 190. IIRC I have the B&M 70274 - similar in dimensions to your Hayden, though a bit thicker.
 
Did some more driving, freeway, and some stop and go in the center of Richmond. Ambient temperature has climbed quite a bit during the afternoon. The transmission topped out at 158°F. Remarkable.
What's also remarkable is that engine temperature remains slightly lower. The highest I saw the engine temperature was 208°F, but that was a very brief outlier; otherwise it remained solidly between 199°F and 205°F, a tighter range than what I'm used to.

I'm very happy with these results. Definitely gives me added confidence in my daily driver.

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