I was able to get the lower line loose on my TH350 with a flare nut wrench, the upper was impossible to access untill the trans was lowered a bit. I was able to use a crows-foot flare nut tool (bought a set of cheap ones from Autozone). If your lines are bent up or damaged, I'd cut them and fabricate or purchase new ones. For what its worth, I bought a $150.00 set of Snap-ON flare nut wrenches for this type of work. I have found they round off stubborn flare nuts just as well as my old Craftsman flare nut wrenches do. :nuts:
Patience and good luck!