Stale water in whirlpool duet front loading washer cannot see water but can hear it if you move the inside of drum

Saw in my local newspaper... Whirlpool won't tell you to maintain by unplugging the machine and removing the front bottom cover of washer (3 screws) ...you will see a valve cover in the center right in front of you....Get towels ready to soak up the water that will spill out when you open this. Remove it and clean the plastic filter and any debris you might see inside then put back together. It worked and wasn't hard to do but now I have other issues with the machine errors and such....I think I'll go back to the old washers minus the electronics.