As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF WHEN A POSITIVE RATE OF CLIMB WAS ESTABLISHED, THE GEAR HANDLE WAS SELECTED TO THE UP POSITION, AND AFTER A FEW SECONDS THE CREW RECEIVED A RED GEAR DOWN INDICATION AND MASTER WARNING ON EICAS OF LG/DISAGREE. THE QRH WAS FOLLOWED AND THE AIRCRAFT RETURNED TO MKE AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE LANDING GEAR SOLENOID VALVE AND PERFORMED GEAR SWINGS WITH NO FURTHER DEFECTS NOTED.