the upper end of the drive shaft 50 an upper portion of the drive cam 68 extends radially outwardly and downwardly over the support ring 66 of the upper agitator portion 46 as seen in fig3 and 6 the cam 68 carries a plurality of dogs 74 fig4 and 5 in a pivotal manner each of the dogs having a tooth 76 formed thereon the tooth being engagable with a row of teeth 78 formed on an interior surface of the upper agitator portion 46 as the drive shaft 50 rotates in a clockwise direction as shown in fig3 the teeth of the dogs engage wi u00b1 h the teeth 78 of the upper agitator portion and cause the upper agitator portion to rotate when the drive shaft 50 rotates in the counter clockwise direction the dogs pivot in the cam such that the teeth 76 of the dogs move away from the teeth 78 of the upper agitator portion 46 and permit the lower agitator portion to rotate relative to the upper agitator portion which in turn remains stationary relative to the washer a bottom surface 79 of each dog lies on an upper surface 80 of the support ring 66 the upper surface 80 also rides against a lower bearing surface 82 of the cam 68 the thrust washer 64 is provided to prevent vertical motion of the upper agitator portion 46 by filling all of the vertical space between the lower agitator bearing surface.