As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER DEPARTURE, LANDING GEAR WOULD NOT RETRACT. GEAR DISAGREE AND GEAR DOORS EICAS MESSAGE. THE AIRCRAFT WAS GROUNDED. REMOVED AND REPLACED LEFT MLG RETRACT ACTUATOR. MAINTENANCE NOTICED THAT THE GEAR HAD BEEN SLOW TO RETRACT AND SUSPECTED THAT IT WAS BYPASSING FLUID.