Rant about Trans Cooler Lines

[jamyers]

So...I want to add a giant transmission cooler to my 2000 Silverado, and I don't want rubber hoses that will rot - I want nice steel lines.

And I want them with OEM-style ends, because that's one thing GM did right, they're simple, I won't have to deal with wrenches rounding off flare nuts or other fittings.

And of course, since it's not an OEM trans cooler, the pre-bent lines won't work.

So I'm looking for some unbent or maybe coiled steel tubing with GM transmission flares on each ends, in a couple different lengths - don't have to be exact lengths, I'm good at bending and can even add in a coil or two to take up extra length and anti-vibration.

Can I find ANYBODY who makes or sells such?

NOOOOOOO!!!

TONS of prebent stuff out there for every vehicle under the sun and TONS of chinese "stainless steel braided ptfe" lines out there, but NO unbent simple steel lines for a custom use???

Oh, I can spend $400 and get a hydraulic flaring tool that will make GM trans flares? Yeah, I'll use that *maybe* 4 times, ain't happening.



GAAAAAAHHHHHH, makes me want to chew up a fender and spit shrapnel at whoever makes decisions like this.

[kwmech]

I get it. I'm currently working on converting a truck to TBI injection. I do have the expensive flare kit you're referring to, but trying to find the fittings............ I did find the male fitting tubing nut from Inline, but finding the female end has been a no bueno. Have called several manufacturers inquiring but they're no help. So back to the wrecking yard to pilfer off of frame rails and convert. It's like trying to find the double flare fitting on the 67-72 fuel sending units that is soldered on

[Accelo]

Do you have the bubble-style fitting on the transmission? I am assuming so.
You can retrofit the fitting back to the flared ones if you like.
Inline tube may have them?
I would recommend it as they are much easier to deal with. Just be careful as GM used both 5/16 and 3/8" lines. It depends on the GVW and year.
Another option is junkyard lines. I have even used the 5/16" compression fittings to connect two lines. I hide the fittings under the engine.

[jamyers]

Originally Posted by Accelo

Do you have the bubble-style fitting on the transmission? I am assuming so.
...

Nope, this one with the 45* entry and 90* backside.



As it turns out, steel brake lines with double flares will work on the cooler end, and I'll cut the GM line and flare it, then use some unions to connect the steel lines to the GM ones.

Still cheeses me that nobody makes straight lines with the GM flare...

[hatzie]

Dorman 800-614 are the female Jiffy Tite transmission line fittings.
The Mastercool hydraulic fitting forming tool works great. Kinda pricey but it works great. Maybe you could find someone to form the ends of a 3/8" Ni-Copp roll.

The SAE J1910 transmission cooler hose lasts 5-10 years. If it's installed with replaceable clamps you can install a new section when it leaks.
The cooling pack is mounted to the body so there's some flex between that and the engine/transmission package. If you don't have the rubber hose to take up the flexion the lines will crack.

[jamyers]

Here's what I ended up doing.
(Using an Eccentric Flaring Tool, which is AWESOME!)

Cut the line coming out of the radiator's trans cooler, then flared the end, connected to a brass flare union, then to a flared steel line, bent to go to around the radiator to the new transmission cooler.

This got annoyingly tricky, because the new transmission cooler uses flares BUT where a flare nut would thread in, it's too deep - the flats of the nut hit the top of the female before the flare seats inside. So...using my old double-flare tool to start a double (or inverted) flare, then the eccentric tool to finish the double flare, that made the flare thick enough to seat before the flats on the top of the nut bottomed out.

Same double-flare drill on the outlet of the trans cooler, then steel line going back around the radiator to another brass flare union, which connects to the newly-flared end of the steel line back to the transmission.

Probably took 1.5 hrs to actually do all that, and 6 hrs looking, poking, thinking, and figuring it out.

[jamyers]

Results:

Max observed trans temp is now 150*F after a couple weeks driving in weather as hot as 100*, generally hovers around 140-145. Can feel a BIG difference in the cooler's inlet and outlet temps, especially right after a drive.

No leaks.

Next up, I'll be fabbing up some rubber grommets and brackets to keep the steel lines from vibrating and cracking.




But I'm *Still* cheesed that nobody makes straight lines with GM trans flares...