I have a 2007 Freestar with the 4.2L and the transmission cooler lines are rusted out where they go across under the radiator. I have looked around for replacement hard lines and can't find anything where I usually get parts (Rock Auto, Auto Zone, CarQuest, etc.). Instead of the replacement hard lines it seems that most places just have high pressure rubber hose (175 psi) for the trans cooler. Broadening my search, I did come across what appears to be the correct hard lines here (#3 and 4 in the diagram), but now I'm wondering if it's worth the extra money to get the hard lines or if I can just use the rubber hose instead. This is what I'm seeing for the rubber hose and adapter fittings, has anyone had experience with this, or any recommendations one way or the other? Thanks!

 

Ok, I solved the issue. Instead of replacing the old lines with matching new hard lines I bought about six feet of the ArmorMark transmission cooler hose from AutoZone, two 3/8" brass compression fittings, two adapters to go from the compression fittings to ribbed ends for the hose to go on, and two ribbed hose adapters (ribbed on both ends) for 3/8" ID hose, and a bunch of hose clamps. Then I cut the hard lines shortly after hem come out of the radiator, leaving enough line to put the compression fittings on, and cut the lines on the transmission end where there is a section of rubber hose on the original lines. I installed the compression fittings and adapters and ran the new rubber hose for both lines. I secured the new hose so it wouldn't hang down and get caught on something, and it's working great, no leaks and no issues, good as new!!