Outboard tranny cooler leak

[SUX2BU99]

I have a reoccurring tranny cooler leak that I can’t figure out. When I bought the truck it had a cheapy fin and tube tranny cooler on it strapped to the radiator. The cooler built into the rad was bypassed for some reason (maybe it leaks or was insufficient). It was leaking where the rubber hoses connected to the outboard cooler so I tried shortening the hose. Didn’t work. It had been double-clamped already so I guess the leak wasn’t new. So I replaced the cooler with a new B&M Supercooler and new rubber hoses. I installed it as per the B&M instructions (strapped to the rad) with the supplied worm-gear clamps (one per connection point). This seemed to work fine but the leak has come back. I haven’t driven my truck in a few months and recently moved so I put a permit on it and drove it. I noticed a small puddle under the front of my truck and sure enough, there was fluid around the connection points. It seems to be worse than before. Now I can’t tell yet if it’s leaking out the end of the hoses or where the hose stubs are soldered to the cooler itself. Any ideas on why this is happening? The rubber hoses are connected to the factory hard lines in the engine bay with the same clamps and don’t leak there. The hoses aren’t strapped to anything for support though. Is my modulator pressure too high maybe? I know it’s been adjusted since the truck upshifts higher than normal (TH350 with a shiftkit).

Thanks!!

[VileZambonie]

Are the clamps tight? Only you can pinpoint your leak bc no one here can see it. No your modulator pressure has nothing to do with it. I would NOT bypass the factory cooler.

[Blazin]

Ditto on the factory cooler. An aftermarket cooler is to supplement the factory one not replace it. Are the hoses made for ATF? If not they will leak no matter how tight you get the clamps. ATF will eat gas line hose.

[SUX2BU99]

Maybe the hose material is the problem. Good call on that one. I think it's regular fuel hose, so maybe it's eating it at the end where the cooler is. No other spots seem to be leaking. I hear you about the cooler being a supplement and not a primary. I don't know why the factory one was bypassed. I could try hooking it back up but I don't know what junk is in there. I should just look at getting a new rad anyway. What do they go for usually?

[werewolfx13]

a 4 core will set you back $300-$350 most likely..lots of copper in them.

[Captkaos]

You should be able to get a replacement 4 core Radiator for around $200.

[Lt.Del]

Chris is right---i  paid $198.00 for my 4 core
http://www.delbridge.net/install

[SUX2BU99]

That's great to know. And with the dollar where it's at right now, anywhere I might be able to buy one from? Autozone carry items like that? I saw a 4-core on Ebay from a C-60 truck for $60 I think. Used of course. Would a rad from a big-chassis truck like that bolt right in? I know they used the same cab.

[Lt.Del]

Look in your yellow pages phone book under radiator.  You have to have a radiator shop somewhere around.  My shop was just 4 miles from my house. They had it in stock.  It bolted right in. 
As far as a radiator from a larger truck--i would shy away from that.  It should be made for our year/model trucks--but you could always take you old radiator around with you and see if the measurements are the same (except thickness ofcourse-allowing for the 4 core) Ensure you have enough room around your fan for the thickness--if all stock, you should. You can always measure the bolt holes. 

[Captkaos]

I agree, any good local radiator shop should have what you need.  If I was buying I would get a new one, you never know what shape a 16+ radiator is going to be in...

[team39763]

I don't mean to hijack your thread, but I think I may have messed up bad.  I took the connections off my radiator(for the trans) and I just put a 40,000GVW cooler in front of the radiator along with an external (oil type) filter.  Will that cooler not be sufficient at cooling my trans?  My truck won't ever be stuck in traffic, and will rarely see more than 30minutes of run time.  Should I go back and try to run the lines to the radiator first?

[werewolfx13]

Yes, you should do that. As I understand it, the radiator cools the trans fluid VERY quickly, but not by a large amount, whereas the external cooler by itself can't cool the fluid very quickly, because the fluid rapidly heats the fins and air takes longer to disspate heat than water does..So you drop the temp VERY quickly with the radiator, then further cool it with the external cooler, which is now handling a more acceptable temperature.

[Captkaos]

Yes you need to use the factory in addition to the aftermarket.