I worked for Sears from 1970 to 1991. In the 70’s most of the washers and dryers were made by Whirlpol, some also were made by Frigadaire and GE. Even a few models were made by Gibson (a heavy combo unit, washer and dryer in one.) Never were any Kenmore washers in the 70’s or 80’s made by Maytag. In those years Maytag and Kenmore (Whirlpol) were bitter rivals. Maytag washers made in the 70’s were tanks but had a major flaw...they did a poor job cleaning clothes.
I think you are right-I believe it was a Whirlpool. Only thing I ever had to do to it was a new water valve. I think it was older as well, as from the 60s.