What was found
NR 2 ENGINE VIBRATION FELT IN CLIMB, OK IN CRUISE. FLIGHT ATTENDANTS REPORTED LOUD NOISE AND VIBRATION FELT IN AFT ENTRY DOOR JUMP SEAT. ALSO, BURNING RUBBER SMELL REPORTED SEVERAL TIMES. DIVERTED TO ORD. *S/D* FOUND LOW FREQUENCY VIBRATION IN NR 1 ENGINE ONLY WHICH WAS CORRECTED BY ADJUSTING THE P & D VALVE. COULD NOT IDENTIFY SOURCE OF ODOR. THE LOUD NOISE REPORTED BY THE CREW WAS NOT ASSOCIATED WITH VIBRATION.