What was found
AIR TURNBACK, ON CLIMBOUT OF ORD EN ROUTE TO PHX AFTER SELECTING LANDING GEAR TO THE UP POSITION THE NOSE GEAR WOULD NOT RETRACT, TURNED BACK TO ORD FOR REPAIR. AIRCRAFT CURRENTLY OUT OF SERVICE. MAINTENANCE REPACKED NLG SHOCK STRUT IAW T/C R4N32305, ALSO REPLACED NLG DOWNLOCK SPRING AND LOWER LOCK SPRING ATTACH PIN PER AMM 32-21-18, LEAK AND OPERATIONAL CHECKS WERE GOOD.