What was found
AFTER TAKEOFF, NOTICED FUEL MIGRATION IMBALANCE OCCURING. RIGHT TANK WAS +600 LBS. DECLARED EMERGENCY. UPON LANDING FUEL TOTALIZER (X) OUT THEN CAME BACK LATER. REMOVED AND REPLACED LSDU IAW AMM 28-41-20, OPS CHECK GOOD. PN/OFF/ON-366-200-001, SN/OFF-1137, SN/ON-1063.