Does Ford recommend changing the o-rings once you take it apart? Seems like a wise idea to swap them out. Once an o-ring is seated, it never really gets back to its original shape or position, then can leak!
When I upgraded to the rxt, I also got a braided steel clutch line. After only a year, the oring on the end that goes into the black plastic piece at the bell housing degraded and was leaking. Seems like they should use better orings.