As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SUBJECT ENGINE RECEIVED FOR MAINTENANCE DUE TO PERFORMANCE DETERIORATION. INSPECTION OF SHAFT THREADS BY ULTRASONIC MEANS IAW SB 72-510 REVEALED CRACK INDICATIONS. CRACK CONFIRMED BY P&W AS BEING INTERMITTENT 2 INCH CRACK TYPICAL OF THE TYPE ADDRESSED BY THE SB. ENG TT: 9,563 HOURS. ENG TC: 6,631.