Leaking at rear of tranny. Replaced rear seal (tail shaft). What is next most likely source of leak?

Drops of red trans. fluid appearing at exactly same places as before we replaced the rear seal.  (Pan, coolant lines, are definitely not leaking). My Sub parks at slight angle (rear down) in the driveway. The drops form at 2 places:  bottom of the semi-circular upside down "hump" at rear of tail-shaft housing, and (oddly) at bottom of u-joint yoke.