In '68 I lost a front wire on my GT6 because the splines spun out. Luckily I was only going about 30mph and making a right turn to leave the town I was in.
The car was a '67 and only had about 50,000 miles at the time. Was court'n Shirley at the time. She lived in a town about 20 miles away and I worked about that same distance from home in the other direction. About 1,000 miles a week at the time. To be fair, I drove like a "bat out of h**l" nearly all the time so it was not a quality issue.
The point I am trying to make is to make certain they are OK.