What was found
AT TAKEOFF THRUST SETTING (ANV) LOUD EXPLOSION HEARD IN COCKPIT AND NR 1 ENGINE LOW OIL PRESSURE LIGHT ILLUMINATED AND OIL QUANTITY DECREASED TO 2 GAL THEN INCREASED TO 3 GAL AFTER SHUTDOWN. ABORTED TAKEOFF AND PERFORMED EMERGENCY ENGINE SHUTDOWN PROCEDURES PER AOM 2-1-2. RETURNED TO RAMP. OIL PRESSURE ALSO DECREASED TO 20 PSI AND CONTINUED TO DECREASE. DISCOVERED T3/T4 HAD SEPARATED FROM ENGINE CAUSING DAMAGE TO TAIL PIPE ASSY. REMOVED AND REPLACED NR 1 ENGINE. OPS CHECK OK. LEAK CHECK OK IAW B727 MM 71-00. (M)