Is a Transmission Cooler Necessary

[Paul Cotton]

I have a 1965 Plymouth Belvedere II with a 440 engine. I am told the car was originally build for drag strip duty by a father and son. The son lost interest and the car was sold as is. The motor is a 440 and is quite healthy, while the transmission is a 727 with a cheater reverse valve body in it. The car is only driven on the street now and while it's capable of setting the tires on fire, it isn't driven that much or that hard.

It came with a transmission cooler mounted in front of the radiator which blocks a significant area of the radiator. I am fighting cooling issues and have changed thermostats, put an electric pusher fan on it and still it heats up.

My thinking is, the transmission cooler is blocking enough of the radiator that it's causing the engine to run hot.

My question is, is the transmission cooler really needed seeing how it's not on the drag strip and it's not driven hard when I take it out.

 

[#41]

Yes it is needed, unless you are ok with a shorter lifespan for your trans.

 

[R413]

What is the stall speed of the torque converter? That's what will build heat.

 

[hofferwood]

Do you have a fan shroud?

 

[1967coronet]

You may be able to switch coolers to a different size & design and mount it on the cool area of the radiator ( down near the lower hose ).

 

[OMTWF-72SE]

I had a custom shroud made for my 440 and its been fantastic, and my trans cooler is up high and almost touching the radiator.

 

[tubalcain]

The factory radiator cooler is all that is required. I drove a kickass car that way for years, street racing for money, high stall convertor. According to your description, you need nothing else.

 

[OMTWF-72SE]

I can't and won't argue with anyone else's experience but my experience with 115 degree ambient temps and 160 degree road surface temps, idling at a stop light is interesting. My original 26" could not cool well enough with my build.

 

[Rusty knuckles]

Have you checked timing? I don't think a tranny cooler is necessary for what you describe but don't think it is hindering your cooling enough to be the silver bullet. I'd also ditch the electric fan for a mechanical (no clutch) with a properly fitted shroud. You didn't mention radiator size either.

 

[Don Frelier]

I'd also ditch the electric fan for a mechanical (no clutch)

He didn't say he had no mechanical fan, only that he installed a pusher.

 

[Sixpactogo]

I have a 1965 Plymouth Belvedere II with a 440 engine. I am told the car was originally build for drag strip duty by a father and son. The son lost interest and the car was sold as is. The motor is a 440 and is quite healthy, while the transmission is a 727 with a cheater reverse valve body in it. The car is only driven on the street now and while it's capable of setting the tires on fire, it isn't driven that much or that hard.

It came with a transmission cooler mounted in front of the radiator which blocks a significant area of the radiator. I am fighting cooling issues and have changed thermostats, put an electric pusher fan on it and still it heats up.

My thinking is, the transmission cooler is blocking enough of the radiator that it's causing the engine to run hot.

My question is, is the transmission cooler really needed seeing how it's not on the drag strip and it's not driven hard when I take it out.

Since it was originally built for strip duty, my question is did they put an underdrive pulley system on it? A lot of guys will install a serpentine belt and underdrive pulleys to cut down on horsepower draw and the cooling system suffers because of it. Also, what type of fan and shroud are you using besides the electric pusher?

 

[Demonic]

Since it is summer, try running no thermostat, or a factory thermostat - with the disc shaped like a cup, or a REAL high flow thermostat like a Stewart/ EMP. Flow is everything, unless the radiator is fouled. A strap-on thermocouple on the outlet hose can tell you a lot.

It is unlikely the trans cooler is a problem. Pusher fans can cause compound issues if the radiator is fouled inside.

 

[Geoff 2]

Yes, you need the cooler, especially if you have a c'ter with higher stall [ they produce more heat ]. The heat hardens the trans seals, they then do not seal, & then clutches & bands start to slip.
Better to try & fix the o'heating. The pump needs to be overdriven 10-20%. This will make a big difference. Use a 160 stat.
What is the ign timing at idle?

More info here on cooling: www.stewartcomponents.com

 

[70bigblockdodge]

Picture of the radiator in the car. Most have low fin count and can't get rid of heat. The engine holds more coolant on a 22" radiator than the radiator, so moving the coolant faster is not helping, just keeping it in the block longer.
Need tight fin count like the aluminum one pictured, lot of cheaper reproduced brass are cheaper because they use less material with loosely woven fins, this no heat transfer to the air.

 

[6PKRTSE]

Depends on several things. My current 440 combo has over 60,000 miles on it. Hundreds of passes with a 10" 3600 PTC convertor with no external trans cooler using the same transmission from even prior to this build since 2007. I just use the factory cooler through the radiator.

 

[zyzzyx]

Bottom line is if it is a strip car and has a 3000 RPM or bigger stall convertor, and you're driving it on the street and not
keeping that convertor "locked" above that RPM then you're making lots of heat! At the strip, that convertor only slips
as you bring the RPM up and once you hammer it, and it gets over the stall speed, the slippage stops and no excessive
heat is being produced. Just driving around town is killing you.

 

[Sparky Anderson]

If you don't know the stall of your converter, it's a very good idea to run a cooler, besides it may extend the life of your transmission.
If your car is running hot, you need to further investgate, is your rad in good shape, are your front brakes dragging if calipers instead of brake drums. I think get the idea.

 

[cudamark]

A trans cooler of some sort is needed. For the street, the factory one in the lower tank of the radiator is the ticket because it not only will cool the transmission fluid once hot, it will also heat the fluid when cold. Warming up the transmission fluid temp quickly will help bring it up to operation temperature (ideally between 160 and 200 degrees) and promote longer life. For a drag car, warming it up isn't much of an issue....cooling it is.....so just a remote cooler is all that is needed.

 

[GTXDAN]

Back when we were racing, late 70s early 80s, we bought a trans from TCI and they told us we didn't need to run one at the track, but if we put it on the street to run a cooler.

 

[Kevin McCabe]

I have a 1965 Plymouth Belvedere II with a 440 engine. I am told the car was originally build for drag strip duty by a father and son. The son lost interest and the car was sold as is. The motor is a 440 and is quite healthy, while the transmission is a 727 with a cheater reverse valve body in it. The car is only driven on the street now and while it's capable of setting the tires on fire, it isn't driven that much or that hard.

It came with a transmission cooler mounted in front of the radiator which blocks a significant area of the radiator. I am fighting cooling issues and have changed thermostats, put an electric pusher fan on it and still it heats up.

My thinking is, the transmission cooler is blocking enough of the radiator that it's causing the engine to run hot.

My question is, is the transmission cooler really needed seeing how it's not on the drag strip and it's not driven hard when I take it out.

Agree with "#41"s answer. If you don't want a tranny oil cooler, then plan on rebuilding your trans on a regular basis. Maybe instead of blaming the tranny cooler, you need to find the source of the heat. I see someone else suggested checking the stall speed of the converter. Have you checked temps with a digital thermometer at both ends of both rad hoses? Do you have the correct size crank and water pump pulleys? If the car was built to race, a larger water pump pulley could have been installed so that the water pump made less parasitic drag. Does the car have the stock radiator in it? All a/t rads have a built in oil cooler. If your rad does, the trans oil needs to go through the external cooler first and THEN back through the cooler in the rad before going back to the trans. A trans that runs too cold is just as big a liability as one that runs too hot. What temp thermostat are you running? Shouldn't be more than 180°F. Do you have good flow through the rad? Start the car up from cold with the cap off and check the flow at the filler neck as it warms up and the thermostat opens. If you don't see lots of flow then there's either a problem with the water pump or a blockage somewhere in the cooling system. You have lots of stuff to check.