A hydrodynamic shaft seal assembly includes a PTFE seal member having outer and inner sections. The outer section is affixed to an annular carrier. The inner section is free and includes at least one hydrodynamic groove in direct running contact with a rotating shaft or wear sleeve. A mid-portion of the seal member is formed between the inner and outer sections. The mid-portion is thinned and includes one or more annular undulations formed therein to improve flexibility of the inner section relative to the outer section. The seal assembly may include one or more excluder features. A rubber casing is molded about portions of the carrier. Preferably, one or more annular undulations are formed in a coining operation during the rubber molding process.