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AT Transmission Cooler

NickD on Mon September 04, 2006 9:56 AM User is offline

Model: 16" by 8 1/2" by 1 1/2"
Refrigerant Type: AT Fluid

This is the AT oil cooler that came with my 82 Pace Arrow with a TH400 transmission, 454 CID engine.



Front view showing lots of fins on 1/16" centers/



End view showing eight 7/16" OD U shaped copper tubes for a total of 16 tubes brazed to the fins.





Connection end showing eight brass U shaped ends brazed into the eight U shaped tubes with barbed hose couplers brazed to the outer two U's.

Found a guy that spend the last 40 years of his life rebuilding the TH400 transmission, has a nice shop and all the tools and is reasonable, came highly recommended. Getting the AT back in a couple of days and wanted to be prepared to reinstall it. Pulled the cooler and cleaned it, they don't make them like this anymore and use a very confusing to me GWV rating. May only get five tubes through fins spaced 1/2" apart.

Have some debris inside the tubes, but still get a pretty good blast through either side, could be eight of the tubes are clear, the other parallel string of eight is blocked. Only have Mapp gas, but not enough heat to melt the braze. Was suggested that I even look into an AC condenser as anything close to this size which is small by comparison is very expensive.

Can try taking it to a radiator shop, but refresh my memory, can brass brazed joints be taken apart?

Can anyone make a recommendation of a good AT cooler?

chris142 on Mon September 04, 2006 11:26 AM User is offline

If that cooler has something built into the tubes to make the fluid spin and twist then theres not much that can be done to clean it. If it's just wide open tubes then you can stick the hose from a slovent tank to it and flush it that way.

I'd replace it myself if there was any question about it. All the auto parts stores sell one thats comparable to it, Prolly smaller but more efficient.

iceman2555 on Mon September 04, 2006 12:02 PM User is offlineView users profile

The more efficient coolers have 'turburlators' built into the tubes. These aid in the increase of heat transfer. Since these units are realitive inexpensive, esp compared to the cost of a tranny rebuild, consider replacment. Hayden makes a very good cooler and is probably the better of the units available. Other manufactures also supply models.
Consider the weight of the vehicle and the weight of the item being towed. Add these together to to arrive at a estimate of the cooler size. A bit larger will never hurt.
This seems to be an older model. Some of the 'copy cat' coolers used the brass tubes and aluminum fins, while the Hayden is all aluminum.

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The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

bohica2xo on Mon September 04, 2006 9:35 PM User is offline

Nick:

I have had to flush a few heat exchangers over the years, I recommend sending that one to the scrap yard. There are much better units on the market today.

The Hayden unit you posted in another thread is good, but there are better units. The hayden uses flat plates, and folded sheetmetal fins between the stacked plates. This works ok but can be a bug collector as you know.

The "mesa" type uses stacked flat plates, that have been embossed with an angular "fin". The plates are stacked with the angles opposing to provide lots of air turbulence - and just as much fluid turbulence inside. Ford has used this type of cooler OEM on some trucks for years. It was originally developed by Mesa, but is produced for B&M, Ford, Tru-Cool, etc. now. Virtually all of the plate area is exposed to air on one side & fluid on the other.

Yes, you can still get bugs in the mesa type but the air side is smooth, and easy to keep clean. They are not expensive, so tossing one after a catastrophic failure is not a huge expense. I do not recommend trying to flush a cooler with 30 (or more!) parallel flow paths. A dirty mesa goes in the trash.

B&M # 70274 11x11x1.5 thick - same as Tru-cool or Mesa the same size.

Bulkpart carries the Tru-Cool:

Tru Cool for motorhome


As always, airflow is important too. I would consider mounting a 12 inch electric fan on a motorhome cooler - since it is possible to apply huge loads at low road speeds for a long period of time.


B.

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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

NickD on Mon September 04, 2006 11:59 PM User is offline

Tru-Cool is more of my style, has a metal mounting system, every Hayden I have seen has no provisions for metal mounting but uses plastic ties that we know won't last. Will dream about that tonight.

Was actually planning on using my old one, cut off that U shaped end with the nipple on it, and low and behold, pulled out long twisted metal strips, 1/4" wide, 22 AWG, with about a turn per inch, that was my rattle and clunk. Did a heck of a job of cleaning the inside, looked brand new, solvent followed by a hydrochloric acid soak with plenty of water to flush it out. With that tee removed, getting a very strong blast from both tube, have confidence in it now that I didn't have before. Planning on make a tee out of brass with a larger opening for the one I cut off.

Not sure about all this talk about aluminum being better, Perma-Cool still uses copper and brass and claims 25% better heat conductivity, my engineering books and experience agree with this, aluminum? It's cheaper. In regards to mounting, found a beautiful spot directly below the engine oil cooler with plenty of air blast from that huge fan.

The guy rebuilding my transmission that's been in the business for forty some years, suggested I reinsert the factory radiator cooler as well, explicitly stated to run the lower transmission outlet to the radiator cooler, then through the aux cooler than return to the upper transmission inlet for far superior cooling.

This transmission cooling is one of the most controversial subjects I have encountered and loaded with contradictions with guys claiming the radiator cooler heats the transmission fluid, not very likely.

On my last 72 Ford with a C-4 in it, darn thing didn't even have an extra cooler and had over 70K on it when I sold it, new own put a lot more miles on it without problems, saw that thing to about five years ago running around town, the cooler in the Chevy is huge, but bypassed. The fan is massive, ha, had a stack of schematics on the rear dinner table, and first time I started the engine with the dog house removed, was like Katrina back there with papers flying all over the place.

Next thing I am reading about is too much cooler where the AT fluid can gel in sub zero weather blocking all fluid flow where the cooler should be bypassed. First question I have is what kind of transmission and what kind of fluid are they using? This is my forth TH400 transmission, first I had problems with, granted, but started my cars at -35*F with no such problems, doubt if I will be using my motorhome in this kind of weather, but can always toss a rag over the cooler if I have to.

For information the parts cost for a complete rebuilt on the TH400 is 300 bucks, new pump, six pad rebuilt convertor with new bearing, all Borg Warner clutches, Torrington bearings, vacuum modulator, all new rubber, etc. and the guy is charging me another 300 bucks to clean and rebuild it. Wife insisted on that extra 300 to keep the smell out of the house, plus this guy has all those special tools, an old guy like me, LOL.

Did hold the Hayden today, sorry guys, not impressed, Tru-Cool looks good, but is made in China, do have a 16 tube, copper, brass, and aluminum cooler that rattles because of those twisted metal inserts that are an inch too short, so which way would you go?

HECAT on Tue September 05, 2006 8:57 AM User is offline

Quote
Originally posted by: NickD


The guy rebuilding my transmission that's been in the business for forty some years, suggested I reinsert the factory radiator cooler as well, explicitly stated to run the lower transmission outlet to the radiator cooler, then through the aux cooler than return to the upper transmission inlet for far superior cooling.

This transmission cooling is one of the most controversial subjects I have encountered and loaded with contradictions with guys claiming the radiator cooler heats the transmission fluid, not very likely.

Next thing I am reading about is too much cooler where the AT fluid can gel in sub zero weather blocking all fluid flow where the cooler should be bypassed. First question I have is what kind of transmission and what kind of fluid are they using? This is my forth TH400 transmission, first I had problems with, granted, but started my cars at -35*F with no such problems, doubt if I will be using my motorhome in this kind of weather, but can always toss a rag over the cooler if I have to.

Did hold the Hayden today, sorry guys, not impressed, Tru-Cool looks good, but is made in China, do have a 16 tube, copper, brass, and aluminum cooler that rattles because of those twisted metal inserts that are an inch too short, so which way would you go?

Nick,

FYI: Hecat pulsating flushers have been used by professional transmission rebuilders for 25 years.

I agree with the recommendation to use the in radiator style cooler with the air over as the high load addition. This is the OEM's recommended method to use the air over unit.

I agree the torque converter will heat the trans fluid as fast, if not faster than the engine will heat the water so it does not really heat the transmission fluid. But the thermostatically regulated water temperature acts as a thermostatic control on the trans fluid, this keeps the fluid at the peak operating temperature as designed.

Today's transmissions (primarily in cold winter climates) are using oil cooler thermal bypass valves for cold weather start-up. The computer system is monitoring for that perfect fluid temp and will probably throw a code if it senses any out of range temps for any period of time. See how adding an aftermarket cooler improperly could lead to the check engine light.

Can't speak to the quality, but the Hayden Oil Cooler is by far the most popular unit sold by the trans parts distributors that we work with.



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HECAT: www.hecatinc.com You support the Forum when you consider www.ackits.com for your a/c parts.

FLUSHING TECHNICAL PAPER vs2.pdf 

NickD on Tue September 05, 2006 1:24 PM User is offline

Hecat, I did look over your flushing system, like it, but just don't have the volume to justify it, many once a year or every other year. Was curious about how many CFM of air yours took and at what pressure, didn't see that specification.

Since I am a make do kind of guy, I just use my sandblasting gun with the smallest orifice, can suck solvent just as well as sand and has quite a blast at 150 psi pressure, doesn't pulsate, but can't have everything.

The only computer in my motorhome is a Dell Axim, and a Toshiba notebook, need the notebook to load in GPS maps into the Axim, actually not even in the motorhome now, but sitting a desk in the house. I like not having a PCM, BCM and all those sensors to fool with, have an excellent AF meter for the fuel, and a spark advance timing light. Drove around town this morning hitting all the auto supply stores, still feel I have the best cooler and purchased a piece of angle iron to mount it in a more intelligent fashion and only planning on using 3" of transmission hose, not the six or so feet that was in there. Yes, I got a piece of brand new transmission line, dealer had three feet of it and said I could have it. Even says transmission line on it.

HECAT on Tue September 05, 2006 3:01 PM User is offline

The Hecat pulsating flushers require about 6 CFM minimum and the internal pressure regulator settings vary from model to model. 100 psi shop air would be sufficient for all models.

I didn't think you were a candidate for one of our flushers for this job, just wanted to share my background into this cooler issue and share my thoughts on the "stock vs aftermarket", "stock w/ aftermarket", and thermal bypass issues you had brought up.

I would go with your best judgement and use the one that you feel is of better design and easier to mount for your application.



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HECAT: www.hecatinc.com You support the Forum when you consider www.ackits.com for your a/c parts.

FLUSHING TECHNICAL PAPER vs2.pdf 

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