Product review (5 stars): Worked perfectly for WM2501HWA
I just replaced this part and the loud buzzing noise when the washer drained is silenced.  The water was still draining out of the washer, but the loud buzzing sound indicated that something was failing.  I watched YouTube videos and researched online.  There were no errors on the control panel, but the buzzing sound was new and indicated that something was failing. Since the sound only occurred when the washer started draining the water, I concluded that it was the pump.
Our LG WM2501HWA has a washer pump motor on the right and this washer drain pump on the left.  None of the YouTube videos had this configuration so it was very confusing.  I have no idea why our washer has two of what seem to do the same thing.  I accidentally took the wrong pump off but it looked nothing like this pump so I put it back and took the other pump off.

Some helpful hints:
Watch YouTube videos - there are plenty
Google the washer Model number - Sears had the parts listed along with the schematic.  Our part was actually 4681EA2001N but this 4681EA2001T (with a "T" instead of an "N") was a recommended replacement.
Take pictures on your phone of every screw that you remove
Place the screws  (by area) in separate bowls and perhaps label them (some of the screws are the same size but have rounded tops)
I like to line the bowls up from left to right as I go so I know how to reassemble
Take plenty of photos of the pumps before you remove them (especially how the wires connect).  There are only 3 screws holding the pump to the black plastic housing but there are about 6 screw holes.  Also, the pump fits are different angles so take plenty of pictures.
Take photos of the hoses and how they attach
Be careful not to over-tighten screws that are attached to plastic
Keep a rag handy because things leak

The absolute hardest part of the whole process was putting that spring around the rubber seal.  I gather they sell a tool that the professionals use but we just grasped both sides of the spring with pliers and pulled.  It took a few tries but we eventually got it.  I don't know if one person alone can do this without the professional tool.

Overall, it's great to do these types of repairs on your own.  Our washer is about 10 years old and I figure we saved close to $300 by repairing it ourselves.  It took about 1.5 - 2.0 hours (even with my errors).  Since a brand new LG washer is about $700-$800, we can put the money towards a new one when we are ready.