A thrust reverser is disclosed for a high bypass ratio turbofan jet engine having a cowling with an inner surface forming an outer boundary of a gas flow duct, the cowling having a plurality of lateral openings and a plurality of thrust reverser doors connected to the cowling so as to be movable between forward thrust positions and reverse thrust positions. The thrust reverser also includes a plurality of linear actuators, one linear actuator connected to the cowling and to each thrust reverser door so as to move the thrust reverser doors between their forward and reverse thrust positions. A synchronization system is included in the thrust reverser and interconnects two of the plurality of linear actuators, the synchronization system having an electric motor, a plurality of transmission drive links, each transmission drive link having one end connected to one of the two linear actuators and a second end, and a gear drive mechanism connecting the output of the electric motor to the second ends of the transmission drive links. Operation of the electric motor rotates the transmission drive links to operate the respective linear actuators to move the thrust reverser doors between their forward and reverse thrust positions. The gear drive mechanism and the connections between the transmission drive links and the linear actuators are such that, in the absence of rotation of the transmission drive links, operation of the linear actuators is prohibited, thereby locking the thrust reverser doors in their forward thrust positions.