What was found
FLIGHT 8291, DISCREPANCY, DURING CLIMB OUT, THE LG INDICATING LIGHTS CYCLED LOCKED TO UNLOCKED SEVERAL TIMES. THE CREW COULD HEAR THE LG BANGING AS IT WAS TRYING TO LOCK IN PLACE. THE CREW TRIED SEVERAL MORE TIMES & FINALLY IT LOCKED IN PLACE. ACFT RETURNED, NO EMER WAS DECLARED & LANDING WITHOUT FURTHER INCIDENT. REPLACED THE LG SELECTOR VLV. RETRACTION NORMAL, OPERATIONS CHECKED GOOD, NO LEAKS FOUND. ACFT RETURNED TO SERVICE.