I’ve gotten some really helpful advice on here, and I truly appreciate it, so I wanted to share this in case it helps someone else. I’ve been taking my time putting my transmission back together, and while watching a YouTube video today, I realized I had made the same mistake shown in the video. Thankfully, I caught it before reassembling my Cub. If you skip ahead to 12:19, you’ll see where the shaft seal was installed backwards.