What was found
ENGINE T-DRIVE (THIS UNIT MOUNTS THE ENGINE FUEL PUMP AND PROP GOVERNOR ONTO A SINGLE ACCESSORY PAD) DEVELOPED A LEAK. UNIT REMOVED AND SENT FOR OVERHAUL. UNIT WAS CERTIFIED AND RE-INSTALLED ONLY TO FIND THE GOVERNOR DRIVE GEAR TO BE THE WRONG ONE. UNIT REWORKED AND RETURNED. UNIT RE-INSTALLED AND OPS CHECKED GOOD. 8.37 HOURS LATER, A GEAR HOWL WAS NOTED ON GROUND RUN. T-DRIVE REMOVED AND INSPECTED. GOVERNOR DRIVE BEARINGS HAD DISINTEGRATED CAUSING METAL TO BE SPREAD THROUGHOUT THE ENGINE OIL SYS. SUBMITTER SUGGESTED CAUSE AS INCORRECT OVERHAUL PROCEDURES USED TO ASSEMBLE UNIT.