What was found
ON APPROACH RNWY 03, CREW LOWERED GEAR HANDLE, GOT 3 RED UNLOCK LIGHT ONLY. EXECUTED GO AROUND. APPROX 15 TO 20 SECONDS LATER, GEAR HANDLE REMAINED DOWN, AMBER DOOR LIGHTS ILLUMINATED & GEAR WENT TO 3 DOWN & LOCKED. DURING THE 15 - 20 SECONDS, ECAM ANNUNCIATED, LG NOT DOWN LOCKED. LG GRAVITY EXT ECAM INDICATION CLEARED WHEN GEAR CAME DOWN. HYD QTY INDICATOR ON OVERHEAD, GREEN, WENT FULL SCALE FULL, THEN NORMAL WITH GEAR DOWN. REPLACED LG SELECTOR VLV 3 GAUGE. LEAK & OPERATIONS CHECKS GOOD & NORMAL IAW AMM 32-31-12-04. OK FOR SERVICE.