Transmission lines with cooler

[AirSpeed]

Getting ready to install a new radiator and got to looking at my tranny lines, they're a mess. The PO did a hack job on them, they've got to be replaced. Should I run hard lines to everything or is it cool to use hose from the end of the line to the cooler and back to the radiator? What is the correct flow, I mean which line goes to the cooler and which goes directly to the radiator? I dont trust anything the po did and dont want to go off his work. Should I make my own lines or just order a set? I have a tubing bender but no flare tool. If I can buy a flare tool and tubing for the same or cheaper price than buying premade lines I wouldn't mind doing it myself. Any tips or suggestions would be greatly appreciated!
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[VetteVet]

This diagram is the correct way to route the lines on all automatics except the 2004r. The lines are reversed on that transmission as far as output and input.
You will need to run some sort of flex line between the engine and radiator/cooler lines due to the engine movement. This can be trans oil hose with clamps or SS lines.




Notice that the hot line on the bottom trans fitting goes to the bottom fitting on the radiator, up through the radiator cooler and on to the bottom of the trans cooler then out the top of the trans cooler and then back to the top fitting on the trans.

[AirSpeed]

Notice that the hot line on the bottom trans fitting goes to the bottom fitting on the radiator, up through the radiator cooler and on to the bottom of the trans cooler then out the top of the trans cooler and then back to the top fitting on the trans.[/QUOTE]



Thank you! That helps a lot! Any opinion on premade or home made lines?
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[DesertCat]

I have always bent my own hardline and been very happy. You can get it at your local auto parts store pre-flared if you want and just get a simple tubing bender.

Never needed any flex lines nor seen that from the factory either IIRC, never had a failure but maybe I'm just lucky.

[TBONE1964]

If it were me, I would hard line as much as possible. Get yourself a nice flaring tool. I would just use steel line that can be bought at Napa or other parts stores. If I am correct, 60 inches is the longest piece you can buy and that should be just long enough with bends to go from the trans to the radiator for one line. You can buy shorter lengths of it for the rest. The line is 5/16 and it will have the correct fittings to thread into the trans and the radiator.You could use stainless but it is a pita to bend and flare and you have to be dead on with the flare or you will get leaks.

You will have to use some rubber at the cooler because of the way it is designed. I would not use over 6 inches of rubber hose.

Take your time and this job will look fantastic. I love paying attention to the smallest details, they do get noticed.

[Andy4639]

I ran steel lines up to the radiator but put rubber hose to it. The fittings were for that so I went with it. Nice diagram Vett.

[airdale94]

You can get a OTC flare tool for $25.00 from Amazon. It just depends on how you want it. Pre-bent will look factory. Bend your-self will look as good as you can bend. Most of the older GM rear wheel drive don't have a rubber flex at the radiator. Alot of cars do though. Rubber is OK if just want to patch it up. Just make sure you tell them trans. hose. You may need double clamps if the lines aren't dimpled. If you're not proficient at bending you can get poly coated steel line, it's a breeze to bend. It's the dark green stuff.

Yes, great diagram Vette!

[AirSpeed]

I just got done replacing the cooler lines, went to NAPA and bought two preflared 60" lines and one 30". Bought a new tubing bender and a foot of hose. To replace everything including buying the new tube bender cost me $48, I ended up only using about 8" of hose because I was able to run the steel lines right up to the trans cooler. It was kinda fun bending the tubing, routing it around everything. I can't believe how easy it was and how fast it went, my bends turned out perfect which I'm choking up to pure luck! I started out really stressing about it then I just said screw it and got busy bending tubing. I did have to solder on some barbed brass fittings to the aux cooler, it had 3/8" tubing and there was no getting that high pressure hose to stretch over.
It was far cheaper than buying pre bent tubing! Thanks for the help guys!
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[JointTech]

Originally Posted by airdale94

You can get a OTC flare tool for $25.00 from Amazon. It just depends on how you want it. Pre-bent will look factory. Bend your-self will look as good as you can bend. Most of the older GM rear wheel drive don't have a rubber flex at the radiator. Alot of cars do though. Rubber is OK if just want to patch it up. Just make sure you tell them trans. hose. You may need double clamps if the lines aren't dimpled. If you're not proficient at bending you can get poly coated steel line, it's a breeze to bend. It's the dark green stuff.

Yes, great diagram Vette!

that $25 tool from amazon doesnt work on steel line. Its worthless. In fact worse than worthless because you waste 5 hours and a few trips back to the store for more steel line.
If you are going to get a flaring tool dont spend less than $100 on it is the word on the street. I just ordered a Rigid for $125 or so. Hoepfully it actually works because it will be my 3rd this week. Amazon and Pepboys versions both failed miserably.

[eagleuh1]

I made steel lines for everything, and used compression fittings with loktite on nuts for connecting to the aftermarket cooler, after cutting off the roled edge. So far no leaks after 20k miles, 3 years or so. Good luck, and another for the more expensive flaring tool.