I know yo found your problem, bu I'll add this in case someone else needs it. Bought a used pto generator, and the shaft wouldn't extend. found that it had a small cable inside, tied around a roll pin at each end, that keeps the shaft from coming completly apart. Evidently the PO had driven away from the gen with the shaft still attached and broke the cable. When he put it back together, the frayed end of he broken cable jammed in between the shaft halves. Had to beat it apart, then removed cable - it works fine. By the way, I lube my inner shaft w/never sieze.