Mostly binding and premature wear of some bushings up front, along with seal leaks. My father was the first man to work on automatic transmissions in Nashville Tennessee in the late 1940's, and I attended a class he was teaching for some of the mechanics in town on Dual Range Hydramatics in 1958, at age 12. GM certified me as a factory-qualified Dual Range technician at the end of the course! I haven't rebuilt one in many years, however!
Jerry
