hello all.

do all radiators have an separate core for transmission cooling?
or just 3 or 4 core radiators? or just big-a&& truck radiators?

when i had my motor rebuilt, we replaced the old stock radiator with a 4-core radiator. the transmission cooling line now goes into the main radiator and comes out again to an auxiliary tranny cooler mounted in front (not sure if the original radiator had a tranny-cooling core).

the aux cooler appears stock ('82 E350) but seems really tiny (about 3x10" or so). So I'm wondring if it would be worthwhile replacing the stock aux tranny cooler with a larger one (maybe 12x12" or so). But if the main radiator loop for the tranny fluid is already additional, then perhaps upgrading the aux is not really necessary?

i guess i should just hook up a tranny temp gauge to determine if more cooling could help under heavy load, but hopefully someone can tell me whether a tranny-cooling core in the main radiator is normal or 'extra'...

Thanx!

 

I am no expert but most radiator tranny coolers I have heard about had a small coil of tubing inside one of the tanks of the radiator(side, or top/bottom tanks).

Nor am I a radiator expert... Usually what people mean by 3 core 4 core etc is how many rows of cooling tubes are in the main body of the radiator. Has nothing to do with a separate core for the tranny, least as far as I know.

I have been told by one tranny shop I trust that the factory aux cooler is enough for my 94 F250 that I use to tow. The size of coolers now can be deceptive. The newer stacked plate types(kinda looks like a honey comb) are more efficient and can cool the same as a bigger old style tube and fins type cooler. The stacked plate cooler on my 250 is something like 12x4x2? if I recall from fuzzy memory. My tranny temps while towing 8,000# in over 100 degree heat on hills rarely gets over 210 and usually runs near 190 for steady pulling.

Get a temp guage and check to be sure, but your radiator cooler and aux cooler is probably enough especially if you don't tow. You can go to a bit bigger cooler, but you don't want to go wild. A tranny does like to be at a certain minimum temp too. Running hot is fatal, running too cold usually just means a little extra wear and maybe sluggish shifting in cold weather.

Just my opinions,

Jim Henderson

 

Jim's basically got it down. There are generally two styles of coolers inside the rad tank, one is the coiled line like Jim mentioned, the other is basically a brass tank. Running a trans too cold is more wearing, and the seals don't get as soft, so some leakage can occur internally (clutch pistons) but a temp guage will help you decide better if anything more is needed.

 

I thought I'd share some recently aquired knowledge. I have the factory rad. cooler on my truck and I am using my old A/C condenser as a tranny cooler(it's about the size of my radiator). My tranny usually ran about 190, getting to 200 in heavy stop-n-go traffic or light grades. It also took a long time to get to temp. A few months ago, I bypassed the rad. cooler, and I am just using the condenser to cool. I noticed that my tranny gets to temp much quicker, and stays cooler(170-190). It also cools much quicker when it does get warm, like after pulling a long hill. For now I will leave it as-is. I will see how it does in the winter as to wheter or not I hook up the rad. cooler again.

 

sycostang, sounds like the radiator loop for your tranny was obstructing flow of tranny coolant. something to keep in mind. thanx all for your info! will install temp gauge and see how she does...