As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ISOLATOR MOUNT RUBBER IS TORN/CUT. THIS CONDITION OCCURS ONLY ON LEARS WITH THE DEE HOWARD TR 4000 SERIES THRUST REVERSERS. THE NORMAL TIME CHANGE INTERVAL IS 8400 HOURS. DEE HOWARD CO. HAS ISSUED SERVICE BULLETINS TO CORRECT THIS PROBLEM THINKING IT IS HEAT RELATED. SUSPECT CAUSE IS VIBRATION OR BUFFETING DURING NORMAL ENGINE OPERATION AND REVERSE THRUST.