What was found
AFTER TAKE-OFF, WHEN GEAR EXTENDED, MAJOR VIBRATION WAS EXPERIENCED FROM NOSE WHEEL AREA. VIBRATION WENT AWAY WHEN GEAR RETRACTED, ALSO FELT IN FORWARD GALLEY AND MID CABIN. MAINTENANCE TROUBLESHOT IAW TSM 32-20-00810-802-S, FOUND TORQUE LINK PIN ASSEMBLY BENT. REPLACED THE CENTER LINK PIN ASSEMBLY IAW MM 32-21-27-400-002-A. AIRCRAFT WAS GROUNDED.