C210 PLT RETURNS FOR MAINT WHEN GEAR RETRACTION CYCLE PRODUCES AN UNUSUAL NOISE.

Narrative

I RETRACTED THE LNDG GEAR NORMALLY AFTER TKOF; AND THE AMBER LIGHT LIT AT THE END OF THE CYCLE; SHOWING THAT THE GEAR WAS UP AND LOCKED. HOWEVER; I THOUGHT THAT THE SOUND OF THE GEAR RETRACTING SEEMED A LITTLE ABNORMAL NEAR THE END OF THE RETRACTION CYCLE SO I DECIDED TO STAY IN THE TFC PATTERN AND EXTEND THE GEAR MANUALLY AS A PRECAUTIONARY MEASURE. THE GEAR EXTENDED AND LOCKED; THE GREEN LIGHT APPEARED; AND I LANDED THE AIRPLANE WITHOUT INCIDENT. I DID NOT DECLARE AN EMER SINCE I HAD NO REASON TO BELIEVE THAT THERE WAS ANY IMMINENT DANGER TO MY PAX; MYSELF OR THE AIRPLANE. I TAXIED TO MY TIE-DOWN SPOT AND WAS SURPRISED TO SEE A CFR VEHICLE DRIVE UP SOME MINS LATER. I ANSWERED THE QUESTIONS ABOUT THE INCIDENT POSED BY THE SAFETY OFFICIAL. I THEN VISUALLY INSPECTED THE GEAR AND CONFIRMED THAT THE DOWN LOCKS WERE FULLY ENGAGED. I DECIDED TO HAVE THE LNDG GEAR RETRACTION SYS INSPECTED BEFORE USING IT AGAIN; AND FLEW THE AIRPLANE TO A REPAIR FACILITY WITH THE LNDG GEAR EXTENDED FOR THE SHORT FLT. THE AIRPLANE WAS PUT ON JACKS AND THE LNDG GEAR RETRACTED. DURING THE RETRACTION PROCESS; A LEAK WAS DISCOVERED AT A SEAL IN THE HYD LINE NEAR THE NOSE GEAR. THE SEAL WAS REPAIRED AND THE LNDG GEAR WAS CYCLED SEVERAL TIMES AND PERFORMED NORMALLY.