What was found
ON FLIGHT 3891 RIGHT AFTER TAKEOFF THE CREW REPORTED RECEIVED A LANDING GEAR/LEVER DISAGREE WARNING. THE LANDING GEAR WOULD NOT RETRACT. THE AIRCRAFT RETURNED TO ORD AND LANDED WITHOUT INCIDENT. THE AIRCRAFT WAS REMOVED FROM SERVICE. AFTER RESETTING THE OVER-RIDE SWITCH, PERFORMED THREE LANDING GEAR EXTENSION AND RETRACTION CYCLES IAW EMB 145 AMM 32-30-00. OPERATIONAL CHECK IS GOOD. NO PARTS REMOVED OR REPLACED. NO FURTHER DEFECTS NOTED. AIRCRAFT RETURNED TO SERVICE.