What was found
SHIP 5645 -ATB- THE AIRCRAFT EXPERIENCED FLT CONTROL ISSUES ON TAKEOFF AND DEPARTURE, HEAVY DUTCH ROLL AND YAW. AN EMERGENCY DECLARED AND RETURNED TO JAX FOR IMMEDIATE LANDING. CORRECTIVE ACTION: PERFORMED VISUAL INSP MLG DOORS, PNL'S, SPOILERS, FLAPS, RUDDER, PCU'S AND RUDDER SERVO DRAINS, NTF. REPLACED YAW DAMPER MODULE AND RIGHT YAW DAMPER ACTUATOR PER B757 AMM 22-21. OPS CHECK GOOD.