If I am not mistaken, this set was right after speed queen dropped using the solenoid system that worked so well for so many years. These washers were problematic. The shifter mechanism didn't work very well and would end up not engaging all the way during agitation. That resulted in damaging the mechanism and the agitate engaging parts. It sometimes ruined part of the transmission also. From about 1970 thru 1979 this machine was made for home units only. The commercial units still used the solenoid system machine until speed queen went to the perforated tub models which were also very problematic. It was the downfall of speed queen in the 70's and 80's.