Our electric slide has a roll pin through the shaft that the manual crank goes over so it's not a socket. In our last unit it had a hex head that was 3/4" so a 3/4" socket fit it fine. I just had a couple of long extensions in order to reach it.
When you post the pics try to get one of the end where the manual crank goes.
Salem 29RKSS Pushing a GMC Sierra 2500HD!
Gotta go campin!