What was found
DURING TAXI A STRONG NOISE AND VIBRATION DETECTED AT MLG AREA. ENGINES SHUTDOWN. TROUBLESHOOTING DETERMINED THAT NOISE WAS PROMOTED BY HYDRAULIC PULSING OF ELECTRICAL PUMPS AND GCU. GCU PLACED IN APU POSITION AND PROBLEM WAS CORRECTED. DURING OVERNIGHT SERVICE, A REVISION PERFORMED TO BOTH MLG, DETECTING WHEEL CAP INCRUSTED IN WHEEL NR 2 OF LT MLG. WHEELS NUMBER 1 AND 2 REPLACED IAW MM 32-40-01. BRAKES CORRECT. REGARDING THE GCU, THE UVC, OIL LEVEL AND CHIP DETECTOR WERE CHECKED IAW MM 24-10-01 AND BEING CORRECT. GENERATION TEST PERFORMED IAW MM 24-2-00, ALL CORRECT.