This picture shows the weird hole pattern in the tub with the blank portions of the tub wall. These solid tub portions were in front of the solid ballast things on the outside of the tub which did something, but I can't remember what. They were not like the ballast tanks on the outside of the fiberglass tubs in some other brands, like APEX. Somebody explained it long ago, but I can't find the explanation. 

This generation also saw the first two cycle timer available with the short cycle for delicates.

Automatic Machine Pump

The gravity drain machines were AM (s) for Automatic Machines. You can see that Maytag did not put a lot of deliberation into the formulation of model designations at this point. I sort of wonder if it were not for the competition changing models and introducing new features every year how long Maytag, left to their own conservative devices,  would have gone on with the original automatics.