Transmission line locations

Hey all. So I'm hooking up my th350 lines 76 gmc. I see some that hook right into the radiator and the other circulates through the cooler in front of radiator. I included 2 pics. I'm curious which one yall think I should go with. I just dropped a 454 in it and getting the th350 rebuilt. I'm figuring they can be hooked up either way, but not sure about the benefits. So any thoughts or advice. Please and thank you

Either way they go through the radiator. With the auxiliary cooler one of them goes through the radiator, out to the aux. cooler then out to the transmission. If you have the aux. cooler, use it, if you dont, you might want to get one. It might help that TH350 live a little longer behind that 454.

An extra cooler will extend trans life. Have 2 aux coolers plus the OEM in the rad on a Sq B used for towing. That might be excessive for most applications, but one additional cooler won't hurt, 2nd picture.

Rather than start a new thread, found this one.

When I got my truck, the radiator trans lines were already disconnected. The radiator was shot for the most part anyway, so I had replaced it with a cold case aluminum. I utilized the existing aftermarket cooler that was already there in front of the radiator.

As it is, there are 1/2 lines running to in front of the engine and finished with barb ends to hoses that go to the cooler.

It’s my thought that I’d like to run the hot line first through the external cooler, then around to the radiator, then back to the transmission. Might put less strain on the radiator cooling the motor that way since some heat would have been removed by that time. My guess is that the radiator trans fluid flow is omnidirectional.

So I’d want a new hard line that runs fully to the transmission,and then a fitting to thread into the upper that I can run the cooler hose to. Anyone have any thoughts?

And what is the standard radiator trans line thread size? Thanks in advance.

Never mind about the thread size- Cold Case website says 5/16 inverted flare.

Still have my ears open if anyone has input as far as flow direction.

Once it warmed up it doesn’t really make any difference.

Some folks recommend the radiator cooler being the last before it goes back to the transmission, since it may add a little heat to the fluid during warmup and it will flow better when the vehicle is really cold. However, I don’t think transmission fluid ever has any problems with flow.

So...you like the cold case? I need to upgrade ours for the 454. I'd have to change to bigger end hoses and extend the upper trans cooling line. They have that in a weird location.

Sgt Gus said:

So...you like the cold case? I need to upgrade ours for the 454. I'd have to change to bigger end hoses and extend the upper trans cooling line. They have that in a weird location.

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If you’re referring to me, I really like mine. Can’t remember who but someone gave me the heads up about the G-van lower hose for the 1.75”outlet. Or just order the one with lower 1.5”. I’ll bet you’ll still get free shipping with the “vice grip garage” code, but I can’t remember if they had spaces between the words.

ChuckN said:

If you’re referring to me, I really like mine. Can’t remember who but someone gave me the heads up about the G-van lower hose for the 1.75”outlet. Or just order the one with lower 1.5”. I’ll bet you’ll still get free shipping with the “vice grip garage” code, but I can’t remember if they had spaces between the words.

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Hmm, the core is 1.45 (7/16") shorter in height than my current. Did you run into that, or no?
I can deal with hoses and transmission lines.

Sgt Gus said:

Hmm, the core is 1.45 (7/16") shorter in height than my current. Did you run into that, or no?
I can deal with hoses and transmission lines.

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My stock radiator was 19”, and so that’s what I ordered. I think they make a 21” as well. Not that it helps what you’re asking.

It does fit a little weird where the runner isolators sit, but I just centered them on the welds where the metal starts to roll over, and bolted it down. It found its way with problem. The metal itself is pretty stout and the welds are pretty thick so I never saw that as an issue as far as where the isolators sit on the welds.

ChuckN said:

My stock radiator was 19”, and so that’s what I ordered. I think they make a 21” as well. Not that it helps what you’re asking.

It does fit a little weird where the runner isolators sit, but I just centered them on the welds where the metal starts to roll over, and bolted it down. It found its way with problem. The metal itself is pretty stout and the welds are pretty thick so I never saw that as an issue as far as where the isolators sit on the welds.

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Good info. Yes I'm looking at the "21" (overall is to top of cap ), but the core is actually 18.80 height. Anyway, seems like I may have like 11/16" above and below core. But that may not be an issue looking at the core support. I just may have to "add" some rubber on top of saddle mounts.
I have to try something. Engineer something. I appreciate your time! All the feedback I can get helps.

Sgt Gus said:

Good info. Yes I'm looking at the "21" (overall is to top of cap ), but the core is actually 18.80 height. Anyway, seems like I may have like 11/16" above and below core. But that may not be an issue looking at the core support. I just may have to "add" some rubber on top of saddle mounts.
I have to try something. Engineer something. I appreciate your time! All the feedback I can get helps.

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Absolutely! I think your attention to detail is just a little bit more than mine. I just said “yep, uh-huh” and clicked on the order button.

If you need to add a little rubber, 5/8 heater hose that just about everyone has laying around cut in half lengthwise works well, then just trim it a bit until you can’t see it. Post some pics and let us know how it turns out!

ChuckN said:

Absolutely! I think your attention to detail is just a little bit more than mine. I just said “yep, uh-huh” and clicked on the order button.

If you need to add a little rubber, 5/8 heater hose that just about everyone has laying around cut in half lengthwise works well, then just trim it a bit until you can’t see it. Post some pics and let us know how it turns out!

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Damnit!!! I only have 3/4 heater hose laying around.

Ricko1966 said:

Damnit!!! I only have 3/4 heater hose laying around.

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Lol, I have both. @ChuckN , yes I'm a little to wrapped in detail. Thumbs up to heater hose. Get r dun