I am working on my first car rebuild of a 1990 5.0 IROC and during the engine pull the hard transmission lines from the 700R4 to the factory transmission oil cooler were destroyed. The really bad part is the ends were lost and I don�t know what the sizes were. Can someone help me with proper size from these lines? I have searched at NAPA and other part stores to just replace the hard lines but can�t seem to find them. So I am figuring my choices are nipples and rubber hose or adapters and AN fittings.

 

1/4" brake lines. Might be 5/16" but I'm not sure if that's a common size so it's more likely 1/4". Tranny and brake line fittings are the same.

 

Repros JUST came out

Contact toxik IROC. I know he bought a repro set, but can't use it now, and wants to sell.

 

Thank you both for the information. If I can get the repros that would probably be easiest.

 

I have short extension lines coming off my tranny mainly because with a tranny shield, the fittings are hard to access. I have 3/8" steel braided hose slipped over the short sections of hard line. I guess from that assumption, the cooler lines are probably 3/8" hard lines. Although I mentioned smaller lines, I wouldn't want to run such a small cooler line.

You need to use a 1/2" wrench to remove the fittings so the hard lines are probably 3/8".

 

transmission cooler lines are 5/16" for 700r4's. Use solid lines only. You can make rubber connections at the radiator or auxiliary cooler if needed as long as you use high pressure transmission cooler line. It is different than fuel line or evap line. Keep in mind that transmission fluid is extremely flammable and can burn your car to the ground/no joke.

 

Transmission rubber line will have "transmission" written on the lines.

 

My bad...Sorry.

It was the ENGINE oil cooler lines toxik has......

 

inline tube in Shelby MI. sells them. just do a search and they should show up.

 

I had to replace the lines also and purchased two 5/16" steel brake lines that were 60" long. They come with the proper fittings at both ends. Please try to prebend and install prior to putting the engine and transmission back in the car. These were very hard to install once the engine and tranny were in the car. Get a tubing bender also so you don't kink the tubing. The two tubes and bender cost $25 at Advance Discount Auto Parts.

 

Thanks for the information on Inline tube. I have an email to them to see if they have the part; it didn't show on their website. If not I guess its time to bend tubes. Unfortunately the engine and transmission are in the car. Well it’s not the first time I had to pull the engine half way back out of the car. I made that mistake when I decided to put long tube headers on the car after the engine was back in the car after the rebuild. As I said it’s my first rebuild. I know I will make a few mistakes but that’s half the fun is figuring it out.

 

Just as an update for anyone who may have these same issues later. I went with the bend new lines option. Yes, the lines are 5/16 brake line. If you haven't worked with bending your own lines before remember that aligning the entry into the fitting on the trans and radiator is critical. We fought for hours to try and get both ends lined up correctly and start the threads into the fittings. The best idea that I had that I could give someone else who goes this route is we decided to cut the lines in half and use unions in the middle. This made the connections much easier then we only had to fight the alignment issues one end at a time and the shorter line was much easier to work with.

 

My engine and trans are in, are you able to describe how they run from the rad to the trans? I cannot figure it out! Thanks!