We have a Whirlpool washer 8 cycle, 2 speed, supreme ultimate care, heavy duty, super capacity. Year made is unknown but probably less than ten years old. Where is the Model Number and the serial number located? I think it has a bad water inlet valve but I cannot order a replacement without Model and Serial number.

It may be visible if you open the door? Some located there.

Here are some manuals: https://dl.dropboxusercontent.com/u/8010163/Whirlpool-Kenmore%20washers.zip
Most water valves are identical so that they are all interchangeable.