Product review (5 stars): Here's why our pump failed
We just replaced the drain pump on our Samsung WF220ANW washing machine, after only 2 years.  I disassembled the machine & replaced just the pump motor, which is part number DC31-0054A. The white plastic sump manifold is unlikely to need repair.

Unfortunately, to replace the pump, you have to reach in from the bottom of the machine - so you have to move the machine and turn it on its side.  Before flipping it over, reinstall the four black plastic "moving holders" to prevent the tub from moving too much and possibly tearing the rubber gaskets.  (I didn't do this, and all went well, but next time, I'll remember!)

Afterwards, I completely disassembled the dead motor, and discovered the cause of failure.  One of my daughter's metal hair clasps had gone into her wash, and gotten caught by the machine's coin-filter.  (that's the cylindrical cleanout on the front of the washer)  I hadn't cleaned the coin-filter in a year; so the hairclasp just sat in the coin-filter.  Sure enough, it began to rust. Drain water pulled rust particles off the hair-clasp, and then past the pump motor propeller. While close to the motor, the rust particles were attracted to the strong magnet that makes up the motor shaft.  Pretty soon, the shaft was covered with little bits of rust; eventually the rust prevented the shaft from rotating.

The pump motor shaft normally gets wet (it's immersed in the drain water).  The electric motor windings are on the outside of the plastic motor, so they stay completely dry.  It's a nice system - as long as no tiny iron particles are in the drain water!

Now that our daughter has left for college, we'll have fewer bobby-pins and hair clasps in the laundry.  And I'll clean out that coin-filter every month or two.