[brooknice]

Yesterday I was driving my 69 gto. It was around 94 degrees out side. My car set up a stroked 400 putting out nearly 500 to the wheels.
Turbo 400 with a gear vendor overdrive. Evans fluid frostbite rad. Every thing over heated yesterday transmission got so hot it would not go over 40mph. I had to park the car and wait a few hours till everything cooled off. I spoke to my mechanic he suggested me getting a rad that didn't have a transmission cooler in it. He suggested getting a separate transmission cooler that we can mount in front of the new rad to stop so much heat from hitting the rad to better cool the engine and the transmission. What do you guys think I can do to cure the engine and the transmission heating problem. I do plan on getting a cold case rad. Do you think that will cure my over heating problem with the transmission and the engine. I would love for the car to run 185 on a hot day. Ohh I will soon be getting ac back in the car. I have derale electric fan. I included the link of the fan and the radiator below.
https://www.summitracing.com/parts/der-16838

https://www.summitracing.com/parts/f...tiac/model/gto

[Squidward]

If you feel your existing radiator is up to the task of cooling the engine, then keep it. Run an external cooler in series with the in-tank tranny cooler. I like to run the external cooler before the tank cooler, but others like it plumbed in after.

Your radiator looks adequately sized. Your fans are pulling just north of 4k cfm. I would have a hard time labeling those as cooling constraints. Now you start running into a ton of other factors that can impact cooling: water pump efficiency, thermostat functionality, pulley size, timing, AFR, air flow path (air is bypassing the radiator).

Water pump efficiency: cast vs. stamped impeller, divider plate clearance. Discussed in detail in this forum section.
T-Stat: Stuck shut?
Pulley size: Smaller water pump pulley makes water pump turn faster, giving more flow. A larger crank pulley can do the same thing.
Timing: more advance is usually cooler, less advance can cause extra heat. This has to be balanced against loss of power or detonation.
AFR: In general, richer is cooler, leaner is hotter.
Air flow path: If air bypasses the radiator, cooling is reduced. The factory sometimes added air dams around the radiator support to force as much air as possible past the radiator.

I'm sure there are other possible causes I haven't touched on.

Personally, I use mechanical fans with clutches and shrouds. I ran an electric fan once, and it didn't work out. I suspected it was inhibiting airflow at cruise speed.

What is your timing? What is your water pump pulley diameter?

[JSPONT]

What Squid said is all good info. I got rid of electric fans, went a 7 blade clutch. It was high 90's here the other day, 120 mile trip, never got over 195 at a light.
I had a tranny cooling issue, I bought the b+m super cooler, did a lot of research they work the best, it is the stacked aluminum style. I mounted it in front of the rad off to the r/side. On cool days it will take the tranny temp gauge 15 minutes to start to move, runs 160. On real hot days 175-180. That is normal driving, making 1/4 mile passes it will get hotter of course but cools down after a bit.

[Chief of the 60's]

Never run a tranny cooler through a radiator. Radiators have coolant and heat. Neither are good for a tranny. Get yourself the largest Hayden tranny cooler made and bypass the radiator. In other words, your mechanic is spot on.

[78w72]

all good info posted by squidward, the rad you have should cool the car, likely something else is causing the high temps like the pump or how its clearanced.

i always run the aux trans cooler in series with the rad cooler, that is how ALL trans & trans cooler companies suggest doing it for a driver car, all out race may be different but still no reason to not run in series. & what happens if you are in stop & go traffic or little to no air flow using just the aux cooler?? you get no cooling, but with the rad cooler, like the factory designed, you still have adequite cooling.

the reason i have read & been explained by trans techs & mechanics is that the rad cooler pulls heat first to operating temps (providing your car doesnt overheat) then the aux cooler pulls more heat & sends cool fluid back to trans. doing it opposite with aux cooler first then to rad cooler will only get trans temps to engine operating temps. on cooler days you want heat in the trans that the radiator cooler will do, too cold is not good for a trans. heres a diagram of how most all trans & trans cooler companies suggest to run the aux cooler. best to have 2 coolers than just one.

[ZeGermanHam]

Something is amiss here. If your trans got that hot under normal driving conditions, it suggests to me that something is wrong other than the cooling capacity. Especially given that you have a GearVendors overdrive unit.

[transam greg]

The arrows showing the direction of the oil flow from the radiator to the aux cooler are going the wrong way.

[78w72]

oops, i posted that diagram before. not sure why they have the arrows wrong, but the basic connections are right, i think its a typo. here is a correct one.

[Steve C.]

TEMP-A-CURE OIL COOLERS
Earl’s offers the solution to marginal cooling systems— race proven lightweight and efficient oil coolers designed to fit in the smallest practical space.

https://www.holley.com/brands/earls/...e_oil_coolers/

B&M also makes a good stacked plate style core for additional transmission cooling.

http://www.bmracing.com/products/cat...t=SuperCoolers


.

[455'73inElCamino]

I am finding in my engine trans setup that my transmission doesn't come up to temperature with the external transmission cool.er. I am considering removing it.

Or is using a transmission cooler thermostat pretty standard practice?

[Chief of the 60's]

Originally Posted by 455'73inElCamino

I am finding in my engine trans setup that my transmission doesn't come up to temperature with the external transmission cool.er. I am considering removing it.

Or is using a transmission cooler thermostat pretty standard practice?

How and where are you checking this?

[455'73inElCamino]

Originally Posted by Chief of the 60's

How and where are you checking this?

I am taping out of the 2004R on the drivers side. I have an LED INDICATOR for temperature ranges that the transmission is at. I just find it hard to believe that the temperature is always indicated being on the low end of its range, which I believe is 130 to 150 F.

The indicator that I bought says to measure the temperature at this point.

[78w72]

Originally Posted by 455'73inElCamino

I am finding in my engine trans setup that my transmission doesn't come up to temperature with the external transmission cool.er. I am considering removing it.

Or is using a transmission cooler thermostat pretty standard practice?

that is one of the main reasons you want to use the rad cooler is series with teh aux cooler... the radiator gets the trans up to a good operating temp fast, then the aux cooler cools the fluid after that. but as i mentioned above, with just an aux cooler & rad cooler bypassed the trans doesnt get to temp fast enough in cool climates.... & with just the aux cooler the trans can get too hot if there is no air flow. for a street driven car, running the aux cooler in series with the rad cooler is the best way to do it in my & most others opinion.

[455'73inElCamino]

Originally Posted by 78w72

that is one of the main reasons you want to use the rad cooler is series with teh aux cooler... the radiator gets the trans up to a good operating temp fast, then the aux cooler cools the fluid after that. but as i mentioned above, with just an aux cooler & rad cooler bypassed the trans doesnt get to temp fast enough in cool climates.... & with just the aux cooler the trans can get too hot if there is no air flow. for a street driven car, running the aux cooler in series with the rad cooler is the best way to do it in my & most others opinion.

I will look to see if fluid goes into the radiator first or the cooler first. I can change it and see if it makes a difference. If it is still cool, I suppose if I eliminated the cooler, it is possible it may be too hot?

In other words, trial and error first, If still runs too cool, add thermostat?

Just mentioning this issue as OP may end up with a similar issue.

[78w72]

if your car doesnt overheat, the rad cooler is sufficient in theory, especially if you verified trans temps are too cool. if car runs at ~180, then thats the temp of the trans fluid being sent to the trans from the rad cooler. if yours is cooler than that on the gauge, either the gauge is off or where its at may read lower. never heard of a trans line t-stat. seems more involved thant it needs to be.

or possible your cooler is too big for the application & drawing out too much heat. heres a chart of ideal trans temps, if your radiator is capable of keeping trans fluid temps in the ideal range, an aux cooler may not be needed for your car or its too big.

but yes, trial & error to determine what your car needs.

[455'73inElCamino]

Originally Posted by 78w72

if your car doesnt overheat, the rad cooler is sufficient in theory, especially if you verified trans temps are too cool. if car runs at ~180, then thats the temp of the trans fluid being sent to the trans from the rad cooler. if yours is cooler than that on the gauge, either the gauge is off or where its at may read lower. never heard of a trans line t-stat. seems more involved thant it needs to be.

or possible your cooler is too big for the application & drawing out too much heat. heres a chart of ideal trans temps, if your radiator is capable of keeping trans fluid temps in the ideal range, an aux cooler may not be needed for your car or its too big.

but yes, trial & error to determine what your car needs.

I suspect based on what you are saying is the trans cooler is too big. I probably overkilled it to be "safe". that being the case, then the fluid probably should go through cooler first, then radiator to bring it to radiator temperature (180F). I will check and try that.

Or as stated, I can try to eliminate it. Radiator I went big on too. Maybe it can cool both engine and tans just fine by itself.

Summary is a transcooler that is "too big" can also be a "problem".

FYI - when I referred to a thermostat, I was referring to something like this:

https://derale.com/products/fluid-co...s/13011-detail

[78w72]

check & see whats going on & whats actually needed. every car is different.

the factory only used the rad cooler, even the HO & R/A & SD cars. so if the radiator can handle both, it should be fine. if you race the car or do any high stress driving a cooler is usually a good idea for the trans... but not all cars actually need them.

i assumed the trans t-stats existed, just never seen one in real world use... to me its just another moving part that can go bad & if you get things right for the car its shouldnt be needed.

[455'73inElCamino]

Originally Posted by 78w72

check & see whats going on & whats actually needed. every car is different.

Will do.

Originally Posted by 78w72

i assumed the trans t-stats existed, just never seen one in real world use... to me its just another moving part that can go bad & if you get things right for the car its shouldnt be needed.

Agreed.

I am sure I just "over engineered" what I needed for problems that I "might" have.

[Ccass]

Originally Posted by brooknice

Yesterday I was driving my 69 gto. It was around 94 degrees out side. My car set up a stroked 400 putting out nearly 500 to the wheels.
. Every thing over heated yesterday transmission got so hot it would not go over 40mph. I had to park the car and wait a few hours till everything cooled off.

Ohh I will soon be getting ac back in the car]

How long did it take to overheat? And when you 'overheated', did fluid spew? Explain the driving conditions you were in.

How do you know the transmission overheated other than you said it wouldn't go over 40mph?


Absolutely forget about running AC until you get this sorted out.

[64speed]

If you got the trans fluid do hot that the trans wouldn’t run over 40 MPH I have to say that’s a new one on me. How did you reach this conclusion? Did it feel like engine braking while you were driving it? I bet that tranny fluid is toast.