Product review (5 stars): Works perfect, simple install
Works perfect, simple install.  When installing on a Kenmore washer - it was a tight fit.  If you look closely at the metal insert, it's by design.  There is a raised portion to keep tension on the motor and impeller shaft, it's not just going to slide on,  Ensure that the shaft is well seated, and is at least flush with the base of the coupler.  Use a socket and a small hammer to tap it fully on the shaft.