Where is the flasher located?
If you look closely you will see one transmission line entering the radiator first, then to the external cooler.
Are you perhaps looking at a power steering cooler?
I just had it all apart today adding an external (non-ford) oil cooler/trans cooler and an external tranny filter. I had mine with the front bumper cover off and the lower plastic pans down. Not to mention some gutter guard for the lower gril openings and some paint for the upper grill trim.
You are correct in that the Trans lines go into the radiator, then to the external cooler and then back to the trans.
The power steering cooler is an unfinned aluminum tube (about 1/4" diameter) which crosses completely across the radiator assys and back again about halfway up and about 1.5" in front of the air cond. heat exchanger.
The external trans. cooler is below the power steering cooler at the bottom of the radiator assy and in front of the air cond heat exchanger. The radiator is behind the air cond exchanger next to the twin fans.
So there are actually 4 seperate heat exchangers in the sandwich.
It can be confusing.
Bilbo




