Are there built in trans coolers in the radiator?

[Mrturner1]

I'm looking at my radiator and on the passenger side there's two steel lines going into the radiator. Are there radiators with built in trans coolers?

[Wrenchbender Ret]

Yes.

[Mrturner1]

The guy I bought the truck from put a TH400 in it if that makes any difference. I was going to get a new radiator and electric fan but if this has a built in cooler I'll keep it and put an electric fan on it to replace the stock clutch fan.

[Grumpy old man]

is the clutch fan bad ? or do you just want an electric fan for the look ?

[leddzepp]

If you are not having cooling issues, I would leave it alone.

[Mrturner1]

Free up the clutch fan drag, and I'm dressing up the engine bay a bit and this huge shroud looks terrible

[Mrturner1]

Is that enough cooler for a 2800-3000rpm stall that's goin in?

[67 chevelle]

your stall should be based on your camshaft profile , 3000 is high for a street driven vehicle

[Mrturner1]

Stall is all setup, I just need to know if the built in coolers are good enough or do I need to mount an external

[leddzepp]

Don't remove the shroud, it is an integral part of the cooling system. The heat exchanger in the radiator is sufficient to keep the trans at operating temperature, unless you do a lot of towing, then adding an auxiliary cooler is a good idea.

[Gimme Jimmy]

If the radiator has small tubing (aprox 3/8) fittings protruding from the large tank, yes it has an trans oil cooler installed. This is preferred to "air over" aftermarket coolers as it maintains a fairly optimal oil temperature for the trans. Make sure it is not cracked. Air test it by plugging one side and attaching a valve and gauge with an air fitting to the other. Open the valve and apply about 10 psi of air (be careful not to use too much) close the valve and note the pressure. Leave it for an hour or more and see if the pressure decreased. If it has, dont use it. Antifreeze and water in the trans is a very bad thing. If you are using a high stall convertor, add an air-over cooler in series (in the line from the radiator) as the fluid coming from the trans will be HOT. This will add cooling capacity and maintain the proper temp. oil to the trans.

[El Dorado Jim]

Hi, I have a th400 in my suburban and my son has a th400 in his truck, I run an added trans. cooler in the front of my radiators,and do not use the radiator cooler at all, I have been told to do this by a few old mechanics, not sure if it is the best way, but have been told that runnung it through the radiator adds heat....jmho

[leddzepp]

Originally Posted by El Dorado Jim

Hi, I have a th400 in my suburban and my son has a th400 in his truck, I run an added trans. cooler in the front of my radiators,and do not use the radiator cooler at all, I have been told to do this by a few old mechanics, not sure if it is the best way, but have been told that runnung it through the radiator adds heat....jmho

Baloney. Liquid dissipates heat more efficiently than air, they are called "auxiliary" coolers for a reason.

[67 chevelle]

you can run an auxiliary cooler , its a good idea , but use the one in the radiator also ,, hook the auxiliary cooler in circuit in the top line going from radiator to trans , this is the return line

[El Dorado Jim]

Originally Posted by leddzepp

Baloney. Liquid dissipates heat more efficiently than air, they are called "auxiliary" coolers for a reason.

that is your opinion, I personally don't want my automatic trans. oil to mix with anti-freeze when the radiator fails, and it happens..google this and you will get all different opinions on whether or not to bypass the radiator, I will stick to the way I have been doing this, works for me

[leddzepp]

Originally Posted by El Dorado Jim

that is your opinion, I personally don't want my automatic trans. oil to mix with anti-freeze when the radiator fails, and it happens..google this and you will get all different opinions on whether or not to bypass the radiator, I will stick to the way I have been doing this, works for me

It is a FACT that liquid dissipates heat more efficiently than air, not an opinion.

But if your setup works for you, and you are scared of the radiator failing, keep on truckin. I'll stick to the way GM designed it from the factory, it's worked for the past 40 plus years.

[davepl]

Yes, a vehicle with a 3000 stall converter should have an aux cooler. And a parachute. I'm taking out and throwing away a 2800 this week as unliveable, so I hope you know what you're doing... no fun on the street whatsoever.

Anyhow, I always run mine first through the aux and then through the factory cooler. My theory being that when it's cold out I'd like the radiator's heat exchanger to warm up the trans fluid and not then immediately shed it back out the aux cooler. So aux cooler first. Not everyone agrees.

So yes, the radiator "adds heat", but only when the trans fluid is cooler than the engine coolant, at which point I (personally) want it to anyway. When the trans is hot enough to need a cooler, it'll be a lot hotter than the engine coolant.

I also advocate (a) all steel lines with no rubber ever, even couplers, and (b) as little restriction as possible if its a trans like the 200-4R that's really sensitive to pressures, as the extra cooler circuit increases line pressure in those.

[Mrturner1]

Originally Posted by davepl

Yes, a vehicle with a 3000 stall converter should have an aux cooler. And a parachute. I'm taking out and throwing away a 2800 this week as unliveable, so I hope you know what you're doing... no fun on the street whatsoever.

Anyhow, I always run mine first through the aux and then through the factory cooler. My theory being that when it's cold out I'd like the radiator's heat exchanger to warm up the trans fluid and not then immediately shed it back out the aux cooler. So aux cooler first. Not everyone agrees.

So yes, the radiator "adds heat", but only when the trans fluid is cooler than the engine coolant, at which point I (personally) want it to anyway. When the trans is hot enough to need a cooler, it'll be a lot hotter than the engine coolant.

I also advocate (a) all steel lines with no rubber ever, even couplers, and (b) as little restriction as possible if its a trans like the 200-4R that's really sensitive to pressures, as the extra cooler circuit increases line pressure in those.

I was told by a few people that a good converter, even a 2800rpm stall will drive normally on the street. You are the first person I've heard say negative things about them, what kind did you get?

[hugger6933]

The name on the box isn't gonna effect drivability but the stall will if your going to that much stall and drive it more than every so often you HAVE to have and aux. cooler ALONG with the one in the truck[radiator] already. Now I had a bigblock Chevelle with a 4500 with the anti balloon stuff and loose for spray but I didn't drive that car much after that on the street. It was no longer fun to drive. sure it had a big cam in it and when I left the stop light police for three towns around would come to see me. The car had to rev way up just to get it to move, but it sounded like a pro mod. I changed the cam out and put in three sizes smaller and picked up .5 tenths in the 1/8 mile from 8.25 to 7.75. but that is a different time and story, if your gonna drive this truck I hope you have the ability to get a smaller stall speed something more like a 2 to 2200 would make me feel better.
I will just say this you don't want your cruising rpms to be LESS than your stall speed. Now with what you have now you might could do it with 5:38 gears but then it is no fun to drive that either unless your trip in it is 300 feet. I hope you can get this worked out I would hate for your[what I feel like]your first hotrod to be undriveable thus a LOT less enjoyable. Jim

[68c10owner]

Originally Posted by hugger6933

The name on the box isn't gonna effect drivability but the stall will if your going to that much stall and drive it more than every so often you HAVE to have and aux. cooler ALONG with the one in the truck[radiator] already. Now I had a bigblock Chevelle with a 4500 with the anti balloon stuff and loose for spray but I didn't drive that car much after that on the street. It was no longer fun to drive. sure it had a big cam in it and when I left the stop light police for three towns around would come to see me. The car had to rev way up just to get it to move, but it sounded like a pro mod. I changed the cam out and put in three sizes smaller and picked up .5 tenths in the 1/8 mile from 8.25 to 7.75. but that is a different time and story, if your gonna drive this truck I hope you have the ability to get a smaller stall speed something more like a 2 to 2200 would make me feel better.
I will just say this you don't want your cruising rpms to be LESS than your stall speed. Now with what you have now you might could do it with 5:38 gears but then it is no fun to drive that either unless your trip in it is 300 feet. I hope you can get this worked out I would hate for your[what I feel like]your first hotrod to be undriveable thus a LOT less enjoyable. Jim

Cheap converters do slip a lot more than a high end like ATI or Coan. They can drive just like stock until you nail the gas pedal. And you can't compare a 4500 stall to a 2800 stall. They are completely different. Hell 2 2800 stall converters could be completely different. You can have one built that is tight on the street and doesn't slip much. Why were you using a 4500 stall for your car anyway? 8.25-7.75 in the 1/8 mile is what, low 12's-high 11's? No need for that much stall.

As for the air or liquid coolers, the air coolers do cool better. Harley have been air cooled for years and have issue and if liquid was better in all aspects they wouldn't make the air coolers. Air rushing past the cooler at speed is much better than pumping hot liquid through a hot radiator with another hot liquid.

[davepl]

Originally Posted by Mrturner1

I was told by a few people that a good converter, even a 2800rpm stall will drive normally on the street. You are the first person I've heard say negative things about them, what kind did you get?

Mine was purple. Sorry, that's all I remember but I bet it's a brand trademark for someone.

Ironically, 5 minutes ago I loaded the stock converter in the back of my car to haul it to the shop to get rid of the 3000 stall! But my cam is 214/218 - pretty mild.

They make "loose" converters, holeshot converters, and tight converters... unless that's all just marketing. Someone above makes it sound like higher quality converters can "flash" to a higher stall speed but not slip much at light load. Hopefully that's the case, but mine slips too much.

My problem was that to get it to creep at all took a fair flash of the the throttle. Going up an incline meant you basically had to run the engine up to stall speed (so going up a ramp, you're at 3000rpm creeping).

Now it sounds like you've got a lot of cam - remember I am doing a mostly stock build. If you're building a street-strip truck and have a big cam then you're on a different path and nothing wrong with a loose converter. In fact you likely NEED one for a big cam.

A 3000 stall converter makes for a pretty spectacular launch if you can get it to hook up though! I had mine in a 4200lb car with a ZZ502 and a properly set up suspension and it launched straight with no wheelspin every time. Fun stuff.

On the street they can get annoying. But that's the price of going fast!

Don't go back to stock stall speed if you do have a big cam without considering the cam. I don't know what a "big" cam is, but if its more than maybe 228 duration @ 0.50? Somewhere around there you need a converter so it doesn't stall out in drive.

Big cam needs big stall speed. Big stall speed can be annoying. So big cams can be annoying. But they make top end power. No free lunch!

[68c10owner]

Originally Posted by davepl

Mine was purple. Sorry, that's all I remember but I bet it's a brand trademark for someone.

They make "loose" converters, holeshot converters, and tight converters... unless that's all just marketing.

My problem was that to get it to creep at all took a fair flash of the the throttle. Going up an incline meant you basically had to run the engine up to stall speed (so going up a ramp, you're at 3000rpm creeping).

Now it sounds like you've got a lot of cam - remember I am doing a mostly stock build. If you're building a street-strip truck and have a big cam then you're on a different path and nothing wrong with a loose converter. In fact you likely NEED one for a big cam.

A 3000 stall converter makes for a pretty spectacular launch if you can get it to hook up though! I had mine in a 4200lb car with a ZZ502 and a properly set up suspension and it launched straight with no wheelspin every time. Fun stuff.

On the street they can get annoying. But that's the price of going fast!

Don't go back to stock stall speed if you do have a big cam without considering the cam. I don't know what a "big" cam is, but if its more than maybe 224 duration @ 0.50? Somewhere around there you need a converter so it doesn't stall out in drive.

Big cam needs big stall speed. Big stall speed can be annoying. So big cams can be annoying. But they make top end power. No free lunch!

What you describe here are characteristics of a loose converter. It's not just marketing. It's the difference between a cheap converter and high end custom built converter.

[davepl]

Originally Posted by 68c10owner

What you describe here are characteristics of a loose converter. It's not just marketing. It's the difference between a cheap converter and high end custom built converter.

Mine is a Vigilante, which I didn't think of as a "low end" converter. Wasn't cheap, that's for sure. But it slips a lot on any incline. Have you heard much on them and how they are relative to other brands he might experience?

[Mrturner1]

I'm gonna stick to the original stall converter plan, I think I'll be happy with the stall speed and the company building the converter, they garauntee you'll love the product or they will send another for free. And it sounds like running an air cooler in front of the radiator, as well as the cooler built into the radiator is the way to go. Somebody explained it earlier, but does anyone have pics of how they tied in an aux cooler with the existing cooler that's in the radiator?

[jocko]

It is not the way to go. If you are reverting to the stock stall plan (a good idea) and you are going to drive normally - the stock, in tank trans cooler is more than sufficient. IF, and only if, you're going to do some heavy towing (or endurance racing..) would it be worth the money. As for risk - there is a much greater chance of a rubber aux cooler line being damaged or leaking than there is of the internal factory trans cooler of failing and mixing with the antifreeze. Has it ever happened, sure - has it happened more than the number of line failures guys have had because of installing an aux cooler with rubber lines? No. Anyway, it's up to you, but if you aren't towing, it's overkill. If you are, recommend a quality cooler that you can plumb metal lines to. And keep the stock fan and shroud - replace the clutch if bad, but it's a good system and it works. This is a great question, by the way, and am glad you asked it. It's one of those that get to the heart of an issue "we" tend to have with our trucks - we always think we can make it better than Uncle GM did. And in some cases, we can. But this isn't really one of em. I've run flex-a-lite fans (blech), and have only really heard of folks being ecstatic about their electric fan setup if they had no other choice - as in a custom engine install with space limitations, etc where it saved their bacon, gave them a way to make the custom setup work. Anyway, either way really is fine - but if budget is a concern, money could be better spent elsewhere. One thing I would do is invest in a trans temp gauge. That will eventually tell you if additional cooling is even necessary.