What was found
WHEN LANDING GEAR HANDLE SELECTED TO UP POSITION AFTER TAKEOFF, RIGHT MAIN UPLOCK BUT WOULD NOT RETRACT. LEFT MAIN NOSE GEAR RETRACTED NORMALLY. A LOUD RATTLING NOISE WAS CONTINUOUSLY HEARD WHEN GEAR RETRACTION WAS ATTEMPTED. ALL 3 GEARS DID DOWNLOCK NORMALLY. RETURNED TO LAX. INSPECTED RIGHT MAIN GEAR, OPERATED GEAR UP AND DOWN MANY TIMES. NO NOISE WAS HEARD AND NO DISCREPANCY NOTED. OPS CHECKS GOOD.