What was found
(CAN) DURING TAXI AFTER LANDING, THE NR 2 PROP MOVED TOWARD COARSE PITCH. THIS WAS DETECTED BY THE AC GEN CAUTION DUE TO UNDER SPEED. THE PROPELLER REMAINED PARTIALLY FEATHERED AT SHUTDOWN & WOULD NOT UNFEATHER AFTER START. EXAMINATION OF THE OVER SPEED GOVERNOR REVEALED DAMAGE TO THE DRIVE SHAFT TEETH. REPLACEMENT OF THE OVER SPEED GOVERNOR RESTORED PROPELLER OPERATION TO NORMAL. SUBSEQUENT INSPECTION OF THE ENG GEAR SHAFT SHOWED DAMAGE TO THE SPLINES. OVER SPEED GOVERNOR GEARSHIFT PN 3122235-01, SN FAGC6066. CONSEQUENTLY THE NR 2 ENG IS BEING REPLACED. THE OVER SPEED GOVERNOR HAD BEEN INSTALLED SINCE NEW.