IMO a crack in a two piece FordoMatic torque converter would be an unusual event.
The FordoMatic aluminum air cooled torque converter is a two piece unit sealed by a rope type gasket. IF your converter is leaking, I would suspect the two piece converter gasket is the source. Another thing to check is whether the two drain plugs on the torque converter housing are tight. -IF someone drained the converter previously for a fluid change, it's possible they did not tighten them adequately. I ran into this a hundred years ago on a Buick Dynaflow transmission torque converter. -The leaking transmission was in fact the leaking torque converter drain plugs!
IF you separate the two piece converter to clean the inside and change the gasket, check to make sure the factory markings for the two housings are properly aligned as original. I've only worked on two of the air cooled FordoMatic torque converters, but on both of those the witness marks were not aligned by the previous person that had the unit apart. -This is a balance thing.
Hope this helps.
NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York