trans cooler line fitting size?


Stock crawlin National...
May 25, 2001
What is the size of the trans cooler line fittings that screw into the factory radiator? I want to put an adapter fitting on it to AN so that I can run AN lines to my external cooler. Thank you.

one more ?.... Is it ok to use quick disconnect fittings on these lines? I see a lot of race cars use them to make pulling the trans easy for convertor changes. I have a street car but dont drive it much. Opinions?

I believe they are 1/8" male NPT adapter to 5/16" pipe.

1/8" female NPT thread in the radiator.
I have quick disconnects on my lines and run steel braided lines through the frame rail on the passenger side so they are out of the way. They work flawlessly. Make sure the inside diameter of the fittings is not smaller than the return fitting in the transmission.
The factory fittings are 1/8"NPT to 5/16" flare and right angle as well.

So the factory radiator should have 1/8" NPT female threads in it.

Make sure your new lines and adapter will clear that space where they have to wrap around, there's not much room there to work with.