I have a '63 Impala 327 powerglide. In the middle of the central tunnel of the x-frame, apparently my drive shaft became loosened and was knocking around. While it was knocking around it busted my fuel line right in the middle of the X.
Your carrier bearing failed. Your car is half a century old parts wear out.
Beware of cheap corner auto parts store replacement carrier bearings which are made over seas (specifically the Pacific Ocean and most of the Indian Ocean). They will not last years never mind the decades that the Factory original lasted. Some are replaced within months of installing their first carrier bearing. The local auto parts store will cheerfully give you another cheap replacement when you bring it back complaining, however they will not reimburse the labor to install it over and over again.