As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FELT STRONG VIBRATION CLIMBING THROUGH FL 235 AND FL 270 FOR 5 SECONDS EACH, THEN AT CRUISE FL 380. VIBRATION 2 TO 3 MINUTES. DURING FERRY FLIGHT TO DAL, CONFIRMED VIBRATION COMING FROM NR 2 ENGINE. REMOVED AND REPLACED NR 2 ENGINE PER MT.