What was found
WHILE SELECTING LANDING GEAR DOWN, SYSTEM HAD TO BE CYCLED 4-5 TIMES, AND CIRCUIT BREAKER TRIPPED. WHEN ACFT WAS PUT ON JACKS, THE 5TH CYCLE, LANDING GEAR WOULD NOT COME DOWN. SHUTTLE VALVE STUCK IN THE UP POSITION (SPECIFIC PART P/N 1280802-1, MANIFOLD BODY ASSY, L/G.