What was found
DURING APPROACH, ALL PRE DESCENT CHECKS COMPLETED, AT FL230 NR 2 GEARBOX PRESSURE FALL RAPIDLY AND ANNUNCIATOR LOW PRESSURE LIGHT CAME ON, EXPERIENCE DROP IN HP AND HIGHER THAN NORMAL TIT. A PRECAUTIONARY SHUTDOWN CHECKLIST COMPLETED, PROPELLER FEATHERED ATC CALLED PROCEEDED TO STRAIGHT TO RUNWAY 18 CYVO ON A SINGLE ENGINE IN RANGE LANDING. SMOOTH LANDING CARRIED OUT NORMALLY AND TAXIED TO GATE. MX CONFIRMED INTERNAL GEARBOX FAILURE FOR THE ENGINE TACHOMETER DRIVE, ENGINE REPLACED, LEAK AND ENGINE POWER RUN CARRIED OUT SERVICEABLE, ACFT RETURNED TO SERVICE.