I have a 225 and 904 in my hot rod roadster with a small tube and fin trans cooler mounted under the body that is leaking. The car weighs 1600 lbs and the motor and trans is stock. I will making adding some performance mods later to the engine 2bbl intake, new exhaust, cam, and head work when I can. Is a trans cooler needed for such a light car? I'm just worried about putting one back up there and a rock or something kicking up and damaging it again. A shield I feel would decrease the airflow and not be worth it to protect the cooler. Obviously my mounting options are limited which is why I'm debating doing away with the cooler.

If you are running the stock type trans cooler in the radiator, you do not need it. If no rad cooler, then you should run an external cooler. You can get the cylindrical finned ones that are super solid.

Lou

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Thanks I will look into getting one. I'm putting my swap meet needs list together!

I have one of the cylindrical finned ones under the Valiant. Doesn't take up much room. Trans temp stays fairly low as far as I've seen so far.

With your setup a stock one in the radiator would be good enough.

Kinda like what Lou said.

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Official Cookie and Mater Tormentor.

It won't be stock for long and I am using a aftermarket radiator to fit the roadster frame. Looks like a cylinder cooler will be the ticket. Thanks yall

Something to think about....as 'hot rodders' we all have added fin type coolers to our auto transmissions. And in a lot of cases, bypassed the stock radiator mounted cooler.

Here in Texas, that's usually OK.

But....in colder states, and in Texas when it gets cold, it's probably not such a great idea. There is such a thing as 'too cold' for fluid, and when you run your fluid through a cooler in 10 degree weather or even 30 degree weather, you probably are creating issues inside the trans. When I drive my cars with fin coolers, I really try to let them warm up slowly and 'easy' until there is a chance, at least, the fluid has some temp in it.

If the aftermarket were really on the ball, you'd see a lot of coolers sold with thermostats (or separate thermostats) that only allow the fluid to be cooled once it's hot. But for the most part no one promotes that.

How about a thermostatically controlled solenoid valve? A bypass line would return fluid to the transmission when the valve is closed.

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1975 Dodge D100 225 c.i., HEI, Parallel Offenhauser, Motorcraft 2150, 904 auto, 9.25" 3.55:1

Sort of when the fluid is too cold it needs the heat of the hotter engine coolant to bring it up to temp.

So..

That thermo. Valve would bypass the finned cooler and send fluid to the regular trans cooler in the rad.

Probably more trouble than its worth.


But in very cold climates it might be needed.

Greg

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The bottom of the radiator (where the stock cooler is) is probably the ideal oil temp.


So run thru the external cooler first, then thru the stock cooler.


Excess heat will be handled thru the external cooler, then the stock cooler gets the oil to the correct temp.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Yea it definitely gets colder up here in Maryland than down in Texas so that is something to definitely think about. This car is a roadster with no top or side windows so it won't be seeing a lot of winter driving.

The reason I've bypassed the stock cooler in the past has little to do with the trans but rather wanting to keep as much heat out of the coolant as possible so the engine runs (hopefully) cooler.

A lot of modern factory vehicles have thermostats, like my 2005 F250. I don't know all the reasons why but as the old argument goes, Ford wouldn't be spending money on that feature unless they knew it was necessary. There are aftermarket t-stats but you have to look pretty hard to find them and they never seem to be just what you want.

I guess for the average dude, like me, it would make sense to gather some data using a trans fluid temp gauge to determine just what the particular vehicle needed. But I haven't done that....mostly because I hardly put enough miles on my older cars for it to matter much.

As big factor is the torque converter. If you had a low stall (or better yet a lockup) the need for a cooler is way less than a high stall which 'works' the fluid much harder.

Here you go'
https://www.summitracing.com/parts/der- ... jIEALw_wcB

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 225 nitrous
64 Valiant Signet
64 Valiant 4dr 170

I've tried those extruded aluminum oil coolers. First a single pass, then a larger double pass then both in series.
They were not very effective and I won't waste my money that way again.

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IMO, I see no reason not to run one of any size. I don't see the major concern in your situation of cool temp warm up issues, and its often said any 10F decrease in Trans oil adds major longevity to the oil/trans. Also remember the cooler is much more effective when the temp delta is greater, ie ambient air or rad water to trans oil temp difference. Any added SS screen should decrease road debris concern issues.

It is true that every 10 degree reduction in transmission fluid temp greatly increases longetivity. That's why the guys who really want their stuff to last forever will freeze their fluid into a solid block of reddish-pink ice.