What was found
(CAN) ON FINAL, CREW ATTEMPTED TO LOWER LANDING GEAR WITHOUT SUCCES. OVERSHOOT WAS INITIATED, LANDING GEAR EXTENDED MANUALLY AND UNEVENTFULL LANDING FOLLOWED. MAINTENANCE DISCOVERED LDG MOTOR WORKING ONLY IN RETRACT MODE. UNABLE TO LOWER LDG ON JACKS. LDG MOTOR REPLACED, RETRACTION TESTS C/OUT, EMERGENCY EXTENSION C/OUT, ACFT RETURNED TO SERVICE. THIS LDG MOTOR HAD ONLY 1472 CYCLES SINCE O/H OUT OF 8000 CYCLES BETWEEN O/H. THE MOTOR WAS RETURNED TO SUPPLIER FOR WARRANTY PURPOSES AND INVESTIGATION OF THE PREMATURE FAILURE.