Hey, I have a 2001 F150 with the factory tow package and tranny cooler and I was in the process of upgrading to a V10 superduty tranny cooler using AN-6 lines and fitting and I have run in to a little trouble. I was under the impression that all the hard lines where 3/8" and goes to find out I am wrong. I cut the return line on the other side of the flex line and it drops down to another size. Does anyone know what size it is and what I can use to transfer from hard line to -6AN line. Thanks

 

Nevermind it was a 5/16'', for what ever reason ford ran the lines from the tranny 5/16'' to a flex line then becomes 3/8''. Then runs threw the radatior, threw the tranny cooler, then back down to a flex line than back to 5/16''. Can anyone explain that logic to me?

 

Yeah, the lines are 5/16, except for the flex lines I think. The input and output on the tranny is 1/4 NPT also. Kind-of random sizing lol. I'm trying to replace the entire set of lines from the tranny to the coolers with braided stainless as my hard lines are bent out of shape pretty bad.