What was found
DURING CLIMB, RIA FLT NR 1111 OUT OF SFO, MAIN GEAR DOORS WOULD NOT CLOSE WITH GEAR HANDLE IN UP POSITION, NOSE GEAR OPERATED NORMALLY. AIRCRAFT DUMPED FUEL AND RETURNED TO SFO. AT SFO, REPLACED 4 WAY 3 POSITION VALVE, PERFORMED OPERATIONAL TEST (DOOR SWING), OPS CHECK OK.