As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT CREW STATED THAT WHILE IN CRUISE THEY LOST 300 LBS OF TORQUE & FELT JOLT IN ACFT. THEY CONTINUALLY HAD A DEGRADATION OF POWER UNTIL LANDING. THE BEST THEY COULD OBTAIN WAS 1,100 LBS OF TORQUE UPON LANDING. ACFT WAS INSPECTED AT SITE OF EMER LANDING & RAN ACCORDING TO MFG MANUALS & FUEL WAS SUMPED TO ENSURE NO WATER WAS IN SYS. ENG MADE APPROPRIATE POWER WITH NO LOSS OF TORQUE, WHILE TEST RUN ON THE GND & SUBSEQUENT TEST FLIGHT. PART WAS REPLACED, FOLLOWING TEST FLIGHT.