I just changed the rear tire today at 152,939 miles. Here's a pic of the drive splines:

They look almost new! BTW, the O-ring is the original, and most of the time I used some Valvoline multi-purpose grease from an old metal can I bought in the 1970s. I could probably have used WD40. For the first 38,000 miles I never even loosened the 4 nuts on the final drive! But later when I did remove the final drive for driveshaft maintenance, I made sure to tighten everything in the proper sequence. That BY FAR is the most important thing to keep in mind when you work on the Lady's rear end! Just be sure to tighten the axle nut BEFORE you tighten the 4 14mm final drive nuts.