Separate Trans Cooler Or Run Through Radiator??

JG71B · Jun 29, 2021

Now the Charger is running and about ready to drive, Im on the fence as to which way to keep the trans cool. I'd like to keep from adding heat under the hood as much as possible. Running an aluminum 3 core, shroud with a 7 blade clutch. Probably fine but, like I said. Anyone have any good/bad experiences with the long, narrow rail mounted coolers. Drive train is all stock and have a cheesy Summit chrome, slightly finned trans pan with a drain plug that may not do a damn thing..., ($30 and dont leak!). Appreciate any input, thanks!

VANDAN · Jun 29, 2021

I'm at the same point, wondering about adding, or just running a large Trans Cooler ? Mine is a 500+ stroker, street/strip cruiser. Will be watching your replies...

moes · Jun 29, 2021

The auxiliary cooler is cooled by air flow while the cooler inside the radiator is surrounded by antifreeze mix which is a controlled environment. I would recommend never eliminating the cooler inside the radiator. If you want to increase cooling capacity add an auxiliary cooler. This way the transmission is being cooled by two different coolers, one with antifreeze and on through air flow.

Cliff Ramsdell · Jun 29, 2021

I have always run my transmission coolers in conjunction with the factory in tank cooler. Route the fluid thru radiator first and then thru the external cooler.

The engine temperature will bring down the transmission temperature and then the external cooler will help to drop it more. The benefits of this setup is in static traffic driving and sitting transmission temps can rise without good air flow over just the external cooler alone.

This advise comes from 30 years as a transmission guy for both Chrysler (84-2004) and my own transmission business.

Cliff Ramsdell

440Coronet500 · Jun 29, 2021

I like/use the plate type transmission cooler. It's best to get some airflow to the cooler. It's not necessary to go through the radiator with an auxiliary transmission cooler. 440'

moes · Jun 29, 2021

Cliff Ramsdell said:
The benefits of this setup is in static traffic driving and sitting transmission temps can rise without good air flow over just the external cooler alone.

this is the reason I tell guys to use both coolers if they want to install a separate transmission cooler. If you get stuck in traffic for a long time the temp is going to climb and climb with very little air flow through the separate cooler (just from the fan at low speeds while stopped in traffic)

66Satellite47 · Jun 29, 2021

I'm on the side of a separate auxiliary cooler for the trans. That separates the heat load generated by the trans from the engine coolant load. You can "tune" them separately. This approach has worked well on my drag motors. My Satellite was built as a street cruiser and has separated cooler systems. It has worked very well in slow/stop & go cruises in 95* weather. 500" EDE head, 10.0 CR. Alum radiator.
For a moderate motor, pure street driver, I'd probably use both in radiator & the proper size auxiliary cooler in series.

493 Mike · Jun 29, 2021

I decided to try this Derale model, thermostatically controlled. Of course I don't have a fuel tank to contend with.
Mike

BSB67 · Jun 29, 2021

It seems like you're past deciding on if you need more cooling.

FWIW, My 500 in motor has no additional trans fluid cooling and seems fine. Unless you are using a loose or inefficient converter the heat build up won't be any different than before 99% of the time.

I usually see them used together in series.

What did Ma Mopar do on their tow packages and motor home motors. I'm sure they used external coolers, no?

JG71B · Jun 29, 2021

What about placement? In front of the radiator of course but, middle, bottom, off to the side, doesn't matter?? I'll assume lowest point middle, wrong? Don't matter?

slepr1 · Jun 29, 2021

I have them placed in series, starting with the rad then to the auxiliary cooler. The extra cooler is not necessary for stock, no load applications unless the circumstances or setup change.
The local rad shop here always advises not to position the cooler in front of the rad. Reason being is to keep any preheated airflow away from rad.

JG71B · Jun 29, 2021

slepr1 said:
I have them placed in series, starting with the rad then to the auxiliary cooler. The extra cooler is not necessary for stock, no load applications unless the circumstances or setup change.
The local rad shop here always advises not to position the cooler in front of the rad. Reason being is to keep any preheated airflow away from rad.

I been wrong all this time then. Always thought front was best but, wouldn't that fair for the trans cooler as well? What's a typical trans normal op temp? Higher or lower than engine? Never really thought of it before

451Mopar · Jun 29, 2021

Cliff Ramsdell said:
I have always run my transmission coolers in conjunction with the factory in tank cooler. Route the fluid thru radiator first and then thru the external cooler.

The engine temperature will bring down the transmission temperature and then the external cooler will help to drop it more. The benefits of this setup is in static traffic driving and sitting transmission temps can rise without good air flow over just the external cooler alone.

This advise comes from 30 years as a transmission guy for both Chrysler (84-2004) and my own transmission business.

Cliff Ramsdell

While the above will result in the greatest transmission cooling, I prefer running the fluid through the trans cooler first, and then the radiator cooler.
1. The trans fluid will run at a more consistent temperature winter and summer (about 170 degrees) either warmed or cooled by the temp of the lower radiator tank temperature.
2. It also puts less heat load on the radiator, so the radiator can cool the engine better.
With the lines reversed, the radiator has to cool both the engine and hot transmission fluid.
This will make it harder for the radiator to cool the engine in hot weather.

I could be wrong, but the '71 Charger is still running the original radiator, with a 5,000 stall converter behind a 700 hp 500" stroker big block.

451Mopar · Jun 29, 2021

The '71-'74 Chargers have alot of room up front. My cooler is set off towards the drivers side, not in front of the radiator.
It is an older tube and fin type cooler. I actually like the plate type coolers, and use them on my trucks. I just never changed the old cooler since it is working fine.
The 727 is using the deep aluminum pan from Cope Racing transmissions. I don't know if it adds cooling, but it seals good and should stiffen the trans case.

moes · Jun 29, 2021

this is my thinking - say your trans fluid is 180 or so degrees coming out of the trans, you route it to a heat exchanger exposed to ambient temps of ~85-90 degrees. This is cooled off noticeably, then you introduce it to the rad trans cooler that has the fluid temp of say 200 degrees as the cooling medium. You just warmed up the trans fluid going back to the trans and negated the trans cooler you installed. That's why I think the trans fluid should go to the radiator cooler first and then to the trans cooler exposed to ambient air to further cool it down, before returning it to the transmission. Just my 2 cents worth.

JG71B · Jun 29, 2021

moes said:
this is my thinking - say your trans fluid is 180 or so degrees coming out of the trans, you route it to a heat exchanger exposed to ambient temps of ~85-90 degrees. This is cooled off noticeably, then you introduce it to the rad trans cooler that has the fluid temp of say 200 degrees as the cooling medium. You just warmed up the trans fluid going back to the trans and negated the trans cooler you installed. That's why I think the trans fluid should go to the radiator cooler first and then to the trans cooler exposed to ambient air to further cool it down, before returning it to the transmission. Just my 2 cents worth.

That seems to make sense thinking about it. Then like 451 said, mount it off to the side up front. Thanks!

Winky · Jun 29, 2021

Ma Mopar also ran it through the radiator first, from the 71 Service Manual:

moes · Jun 29, 2021

one mistake I see is guys placing the cooler right against the rad and using those plastic ties. I think that is bad because you are going to draw heat from the rad to your cooler. I tell them you should have at least 1 or 2 (or more) inches away from the rad. That way you will get a better air flow through the cooler you are using and take advantage of the extra cooling.

493 Mike · Jun 29, 2021

BSB67 said:
It seems like you're past deciding on if you need more cooling.

FWIW, My 500 in motor has no additional trans fluid cooling and seems fine. Unless you are using a loose or inefficient converter the heat build up won't be any different than before 99% of the time.

I usually see them used together in series.

What did Ma Mopar do on their tow packages and motor home motors. I'm sure they used external coolers, no?

They sure did and always in series with the radiator cooler.
Mike

CoronetDarter · Jun 29, 2021

Winky said:
Ma Mopar also ran it through the radiator first, from the 71 Service Manual:

View attachment 1131356

That's the same illustration I used to route my Coronet's lines. I'm using a Derale plate type cooler about 1' x 1 1/2' mounted ahead of the radiator with 1" spacers, a B&M deep, finned pan. I have a temp gauge with the sensor coming out of the pan. The engine is a 440, puts out about 500 hp, hooked to a 3,000 stall converter. The trans runs 180° in traffic, 20° lower on the freeway.

Separate Trans Cooler Or Run Through Radiator??

Well-Known Member

FBBO Gold Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

FBBO Gold Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Member

Well-Known Member

FBBO Gold Member

FBBO Gold Member

Similar threads