904 brakes torgue converters

I had a 79 5th Ave with a 360 and 904 lock up than ran very well. One day it started making a ticking sound at the back of the engine almost like a lifter noise. When I finally figured it was from the transmission I found like you did, half of the converter snout had cracked and broken off. I replaced the converter and pump bushing and drove the car quite a while before I sold it. I have no idea if it failed again later but I thought it odd also. The shop that supplied the converter said it was not that uncommon though.