shaft 910 is internal to and concentric with outer shaft 920 inner shaft 910 is connected to and driven by a rotor 940 a cylindrical coupler 930 includes a lower portion 932 an upright portion 938 and a locking flange 939 extending radially outward from upright portion 938 locking flange 939 includes an upwardly extending locking rim 937 coupler 930 is concentric with inner shaft 910 and outer shaft 920 upright portion 938 of coupler 930 includes a plurality of internal splines 936 at an upper end thereof splines 936 are configured to engage a plurality of external splines 924 on outer shaft 920 lower portion 932 of coupler 930 includes a plurality of internal splines 934 configured to engage a plurality of external splines 912 on inner shaft 910 coupler 930 is free to slide along outer shaft splines 924 rotor 940 includes a central recessed portion 942 that receives lower portion 932 of coupler 930 when coupler 930 is at the lower end of its travel inner shaft 910 includes a spline free section 914 adjacent rotor recess 942 such that coupler 930 is disengaged from inner shaft 910 when coupler 930 is seated in rotor recess 942 a number of locking pawls 976 are pivotably attached to washer tub 970 through a plurality.