[DonC]

Thanks for all the input and advise.
Fortunately the head of the plug isn’t stripped yet and I was able to find a ½” 8 point socket. I’ll try it this spring when I drain and refill the differential again. Since the plug head is a generous ½” I still may have to go the easy-out route but I’m keeping my fingers crossed that I won’t have to. If I do have to go easy-out I’ll pick up a replacement plug and machine the head to a true ½” for future work.
This time I was able to suck the existing lube out with a fluid extractor and got (I think) almost all of it. It just would have been much easier if I could have gotten the plug out.
Also picked up a 9/16” 8 point, which fits the TKO600 plugs, although I can get to those with a regular wrench.
DonC