With ANY Pto shaft, always remember to measure at the tightest point which may OR MAY NOT be when the implement is on the ground. it all depends on the location of the driven end of the implement in relationship to the PTO output stub.
It's very important that the shaft is never put in a bind (that is no sliding clearance between the halves because at that point (no sliding clearance). the PTO shaft is exerting a pushing pressure on the PTO stub and will not only destroy the internal bearings, it will destroy the shaft seal as well.
The bearings that carry the PTO stub aren't designed for a push or pull load, only a radial load.