Replacing transmission lines

mcnoople said
Why not just put the rubber hose for flexing at the trans and mount the metal hardline to the body? The front cooler is mounted to the body so there shouldn't be any flex there. If you mount the hardline to the body instead of the engine you can just run the trans line along the frame rail all the way forward with minimum bending required and no snaking around exhaust pipes.

Some people do it that way to put a long, thin trans cooler along the frame rail. Not having metal cooler tubes in the way might make repairs easier too, like adjusting the front kickdown band (as I did last night). I suspect the factory ran them along the engine to simplify assembly.