Radiator without trans cooler??

[JTex_4]

I have come across a new radiator for a 302 manual. Came out of a 74. I’ve got a 74 with an automatic so my radiator has the trans cooler lines. This new one does not.. good idea? It’s hard to pass up with my radiator being no good but what are my options for the trans cooler? I’m sure I could buy a trans cooler and new lines and run it separate from the radiator, just looking for input.

 

[jw0747]

Automatic tranny would burn up without a cooler. You can have a manual radiator w/o tranny cooler but in it's place you'd need an auxiliary cooler mounted somewhere to cool the tranny fluid. Most all vendors, Jeg's and Summit have auxiliary coolers similar to this one from Wildhorses.

https://www.wildhorses4x4.com/produ...e_Transmission_Cooler_Kit/Bronco_Cooling_Fans

 

[Broncobowsher]

Not a good idea. Even with an aftermarket oil to air cooler there are still good reasons to run a stock oil to water cooler.

Work a torque convertor hard (which is real easy in a Bronco) at times where you have little airflow across the cooler and the temp will spike. An oil to water cooler can dump that heat into the mass of the water. Even today every new car with an automatic still has a cooler inside the radiator. Usually with additional oil to air coolers. And on new stuff they also run water to oil warmers to heat the transmission fluid (cold weather, long drives with a locked torque convertor).

 

[Rustytruck]

I run my Bronco with only a separate transmission cooler. Being in socal we do not deal with cold transmission fluid. So if you live where your dealing with extreme cold, a coolant to oil cooler may be much more important. What is very important is proper gearing to the size tires you run other wise you may overheat the transmission fluid in the converter.

28" tires stock 3.50 gearing, 33 ' tires 4.11 gearing and so on. Gearing is extremely important to the torque converter performance in the C-4 transmission.

 

[jw0747]

I run my Bronco with only a separate transmission cooler.

X2 My radiator tranny cooler has been blocked for years and max trans fluid temp is about 175 degrees. C4, 35" tires, 4.56 gears.

 

[Broncobowsher]

X2 My radiator tranny cooler has been blocked for years and max trans fluid temp is about 175 degrees. C4, 35" tires, 4.56 gears.

And you have enough gear for the size tire. That makes a huge difference. Play on some rock piles and I bet you will see a spike.

 

[sanndmann3]

I run only external trans cooler. My previous transmission went out and polluted the cooler in the radiator. Its impossible to clean the internal cooler but I didn't want to throw away the fancy aluminum radiator so I bypassed it. (also, trans cooler was in hot tank as it was reverse rotation...)

Make sure you get a new, stacked plate cooler rather than tube and fin. Its much more efficient. Also consider getting a gauge to keep an eye on things...

 

[Broncobowsher]

A couple years ago I was on a TV film shoot for an off-road show. They were running 5.38 gears and 37s. After about 5 minutes of crawling on rocks the computer controlled transmission went into a limp mode, overheated. I checked the build. The in-radiator cooler was not hooked up because they didn't want it causing the engine to overheat. So we would let it idle and pour ice water on the oil to air cooler to bring it down. Then roll cameras and film another 10 minutes. The engine was never making enough heat for the fan to come on. But the ATF was hot enough and had no cooling.

I am also guilty of having a custom radiator built and put in an engine oil cooler on the cold side just to cool the ATF. Nobody considers upgrading the in-radiator cooler. But it can be done.

 

[mattyq17]

I am in the same boat. The PO put a C4 with no cooler and the stock 66 289 radiator. I was looking at a new radiator with a cooler but reading here an external cooler might work for my needs. Weekend cruiser with some dirt road/forest service roads mixed in occasionally. No rock crawling or dune running. 289 4.10 gears 31x10.5 all terrains. Which external cooler would you all suggest or should I just go with a new radiator with the tranny cooler?

 

[Broncobowsher]

4.10s and 31s, no hard use, big stacked plate. That is the quick and cheap way out. At least a 5x8x1.5 or larger

 

[OKLA70]

I was running a C4, D20 (recently went to an Atlas 3.8) and 4:10 gears on 38" TSL's. I have a cooler with a fan and another cooler in front of the radiator. it normally ran about 180. Granted I'm not too hard on it, so that helps.

It can be done.

 

[Rustytruck]

Mine is a very large stacked plate.

https://www.summitracing.com/parts/bmm-70274/applications

 

[JTex_4]

So... 3.50 gears and 31x10.50s is going to be questionable with.. my rig has no plans on seeing rock crawling, just cruising.

 

[Rustytruck]

Its not ideal for what the truck was designed for. Load will get worse if towing a trailer or slow crawling steep stuff. If you do go offroad high 4wd will mostly be useless. You will want to go to low range 4wd much earlier than most people would want to. Torque converters make allot of heat trying to overcome tire and gearing mismatch. Around town it will not be a big deal for the most part but ask the engine to work harder pulling a load is a whole other story. The more rpm you use to get where your going the more heat you will produce to get there. You need to be able to remove that heat. The cooling system on a Bronco is designed around a stock Bronco with its driveline as designed. There is not an abundance of extra capacity built in, once you start changing things. If you look at all the heating complaints in all of our Bronco threads you don't see allot of overheating problems on a pure stock Bronco other than maybe replacing a plugged radiator or a rusted out head gasket. Automatic tranny fluid doesn't like heat you cook it and you start having tranny problems. If it isnt bright red and stays bright red you have problems.

 

[blubuckaroo]

I may sound like a good deal. But by the time you buy an air cooler equal to that little liquid heat exchanger unit in the radiator, you're not only going to spend more, but you're going to give up a lot of space.

 

[JTex_4]

Thanks guys, makes sense! I’ll hang tight and just buy a stock radiator when the time comes. I’m about to start on floor pans so it will be out of service for a little while anyways!