Abstract: A hub locking system for a part-time four-wheel drive vehicle including a wheel hub, drive axle, and clutch meaner and an automatic actuator remotely operable by an operator to induce movement of the clutch member axially inwardly and a biasing means acting against the clutch member opposing operation of the automatic actuator to urge movement of the clutch member outwardly. A manual override allows manual operation when the automatic actuator is not actuated and includes a first member mounted for shifting axially inwardly and outwardly in the system and when shifted inwardly urges the clutch member against the force of the biasing means. A second member is mounted contiguous the first member and is manually rotatable. A ramp shaped cam is interposed between the first and second members and when the second member is rotated, it directly urges the first member to shift axially to actuate the clutch member.