What was found
YUL - FLT T2037 - AFTER TAKEOFF YUL EN ROUTE ORD, LANDING GEAR WOULD NOT RETRACT WITH GEAR HANDLE IN UP POSITION. RETURNED AND LANDED YUL WITHOUT INCIDENT. STOWED GEAR DOOR BYPASS HANDLE IN FULL CLOSED LOCKED POSITION. SYSTEM GROUND CHECKED, NORMAL OPERATION. (X)