What was found
THE PILOT STATED HE HEARD A FUNNY NOISE WHEN LANDING GEAR WAS RETRACTED. WHEN LANDING GEAR WAS EXTENDED TO LAND, DID NOT GET A SAFE INDICATION ON LT MAIN GEAR. UPON LANDING, ACFT SETTLED ON ITS GEAR, ROLLED SEVERAL FEET AND THE LT GEAR CAME OFF OF THE ACFT. THE ROLL PIN (NAS561P4-28) THAT RETAINS THE UPPER TRUNNION PIVOT PIN (0841011-1) IN PLACE HAD SHEARED ALLOWING THE PIVOT PIN TO MOVE FORWARD WHICH ALLOWED THE GEAR TO COME OFF OF THE ACFT.