If you have an older model WM8000H_A you MUST pay attention to the type of door gasket (boot seal) that it uses. Every video I could find for replacing the seal on the WM8000HWA involved a different product than what was required for our specific washer. I wound up getting the wrong one by ordering it without help and had to exchange it - after I had the machine taken apart. Thanks to AppliancePartsPros I got the correct seal and front retaining ring the next day.
NOTE! The retaining rings are hugely important. There's an inner and outer ring and they are different sizes. The ring that I received for the inner installation was the wrong one so I used the one from our original seal. It worked fine. The new front ring was correct.
The process is really pretty straight-forward after watching a few of the videos. But note also that if your machine uses the same seal as ours, I found it totally impossible to install the outer retaining ring using ANY of the methods seen in the videos. I finally found a video that showed the use of an actual LG branded ring clamp expanding tool. The one I found was about $50 (ouch!) but I'm certain I would not have been able to finish the job without risking damage to the washing machine and/or the brand new seal. I believe that in later versions of the same model washer they changed the shape of certain parts involving the boot seal and installation of the retaining ring is much easier. Save yourself some major time and aggravation by purchasing the expansion tool ahead of time.