Ordered the gasket first from Sears, but they sent me the wrong part, i.e. on the drawing on their web site the part was right (ADX73550621 - Refrigerator Door Gasket, Left), but when I received it - it was too small and didn't fit. Returned it to Sears and tried to find it somewhere else. Fortunately found the part on this site. It was helpful that the part photo was taken with an inch grid in the background, so I could compare dimensions against the old piece. The dimensions matched (wanted to avoid having to return it again) and I placed the order. The right part number is AP5780529 (LG Gasket Assy, door). It took 2-3 days to arrive. The actual repair was straightforward. It took about 15/20 minutes, but only because I let my 12 years old son do it so he could practice his fine motor skills (something sorely lacking in his videogame generation!). Your youtube clip ( https://www.youtube.com/watch?v=LuSTFHcT04w ) helped somehow, but was too complicated. There is absolutely no need to remove the refrigerator door, you can work perfectly fine with the door on. So:
1 - Unplug and open the fridge
2 - Remove the door flipper on the left side. To remove flipper - remove the two screws that hold the flipper to the door, slide the flipper up and unplug the little cable from fridge to flipper.
3 - Pull the old gasket out by hand
4 - Put the new gasket in place by pressing it in with fingers, starting from any upper corner
5 - Lastly return the door flipper in place as per instructions in step 2, but in reverse
6 - Inspect visually the gasket fits smoothly in and the door closes well
...and you're done. Thanks for sending the right part!