What was found
AIRCRAFT WAS GROUNDED: THE GEAR FAILED TO RETRACT AFTER TAKEOFF ALL RED DOOR LIGHTS AND GREEN GEAR LIGHTS WERE ILLUMINATED. WE RAN THE LANDING GEAR DISAGREE CHECK LIST TWICE THE GEAR RETRACTED WHEN THE FIRST OFFICER HELD THE MANUAL GEAR EXTENSION DOOR CLOSED. PERFORMED BITE TEST OF PSEU, PER FIM 32-09-00-810-801, NO FAULTS FOUND, ACCOMPLISHED MANUAL EXTENSION SYSTEM ACCESS DOOR SWITCH ADJUSTMENT, PER AMM 32-34-00-820-802, PERFORMED INSPECTION OF LANDING SELECTOR VALVE, FOUND NO LEAKAGE. AND PERFORMED INSPECTION OF GEAR PROXIMITY SWITCHES, PER AMM 32-09-12.