When starter was rebuilt, had them replace everything on the drive end. Bendix and drive gear. All the old parts looked good and showed no damage at the starter, but shafts were dry so I assumed new parts and some lube would suffice. The damage I found on the ring gear did not appear to be bad enough to keep vehicle from starting once the teeth were cleaned up, unless the starter is not driving the teeth far enough into the ring gear to get a good grip on it. If this is the case, the design is junk and Ford needs their collective [expletive deleted] kicked. I expect better than this on an $18K car.
Thanks to all that replied. You told me exactly what I didn't want to hear, but highly suspected.
Dialtone