The shaft is held in by the set screws on the gear hubs: 1 on the cam gear, 2 on the little pinion gear 90 degrees apart. Loosen them 3 turns or so with a jewelers screwdriver.

Slide the pinion gear to the end of the shaft. Gently slide the shaft back with needle nose pliers. Catch the gear before it falls.

Push the shaft out the back then finish pulling it out.