As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT NR 3241 (LAX/CLD), PILOT REPORTED THAT THE LANDING GEAR WOULD NOT RETRACT ON TAKEOFF. THE AIRCRAFT RETURNED TO FIELD. MAINTENANCE REPLACED THE NON RETURN VALVE AND THE EMERGENCY HYDRAULIC SELECTOR VALVE IAW JSM 29-00. MAINTENA NCE PERFORMED MULTIPLE GEAR SWINGS IAW JS32 MM. THEY COULD NOT DUPLICATE THE PROBLEM; OPERATIONAL CHECKS WERE GOOD. THE AIRCRAFT WAS RETURNED TO SERVICE. P/N CHANGED AIR873601 & 7448.