Not trying to hijack the thread but I'm researching trans and engine oil coolers. What did you install? and where did you mount it?Welcome to ROF!
I also have a 2004 Auto Rubi. Are you asking about the metal to rubber stock lines that go to and from the transmission directly? I did some looking and ran into the dead end you did. I put in an auxiliary cooler in mine using rubber transmission hose, but I've never fabricated off the transmission its self. I think I read on here some years back about a similar question. You'll get more feedback soon.