I am not one of the Tech Gurus here but I think I can answer your question.

Replacing the water pump on a Whirlpool Top Loader ( I am assuming this is a top loader) is one of the easiest repairs you can do. The cabinet can be taken off and put back on in less than 5 minutes.
But it is not obvious how it comes off.
I just about destroyed my wifes old Kenmore washer years ago trying to get into it.
Go to Google and type in replace Whirlpool washer water pump on search for videos. There are plenty that show how to get the cabinet off, replace the pump, and put it back together again.

As I said- it is a very easy repair once you see how it is done.

The part number for the new pump is: AP2908525

APP is the best company I have found for Appliance parts and I have bought a lot through the years from them. You came to the right place.