Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Aircraft Equipment Problem Less Severe
Flight Crew Landed in Emergency Condition
Aircraft
Normal takeoff from Runway 22R in KEWR.  International flight.  After gear lever was positioned up; we got an EICAS message Gear Disagree and Gear Doors.  We completed checklists for both but could not get the EICAS messages to go away.  Coordinated with Chicago Dispatch and New York TRACON while attempting to solve problem.  We then [requested priority] with New York Approach Control and returned to Newark Airport.
Everything about flight was normal and SOP (except that Ctr ADP Auto position was deferred) until gear retraction. Gear was placed in 'Up' position and after about 30 seconds we get EICAS messages GEAR Doors and Landing Gear Disagree. At first; I thought the issue was related to the Ctr ADP (ADP switch was in ON position) and that gear was just slow to retract. Gear synoptic showed nose and right gear to be UP and left gear was in transit. When it became apparent that there was some other issue; I instructed the FO to maintain 230kts in clean configurations while continuing to climb. We could definitely feel that there was something in the slipstream. As this was happening the two International Relief Officer were reviewing both QRH procedures for the malfunction. There was discussion as to what we thought was happening and our options. The QRH procedures didn't really lend themselves to troubleshooting; but mentioned max airspeed with gear down. We did slow to 180kts in attempt to get gear up and doors closed per QRH. SATCOM call with Dispatch and Maintenance lead us to try and cycle the gear. Gear handle was put in down position and a DOWN indication was received; but GEAR DOORS message was still there. After consultation with Maintenance; Chief Pilot; and crew; it was unanimously decided to not raise the gear for fear of not getting another DOWN indication. [Priority was requested] and uneventful landing was   accomplished.
B767 flight crew reported EICAS gear anomalies on departure resulted in a return to airport.