Torqueflite 904 rear seal

The seal came from a company called fatsco. Their website was pretty specific and offered insight in line with what you’re saying regarding how 65 was a unique year. I switched from the ball and trunion to a universal joint driveshaft , and thought I’d be thorough and change the seal while it was apart. It had a small leak. Then boom. A big puddle. What are your thoughts on that seal needing to be broken in some? No puddle yet. Just scared of reoccurrence. Thx for your reply!