A transmission is provided that includes at least first and second rotatable shafts, at least first and second pairs of meshing gearwheels, each of which includes an idle gearwheel rotatably mounted on the second shaft, at least one synchronizer which is displaceable along said second shaft between first and second engaged positions in which it locks one of the idle gearwheels to the second shaft via a neutral position, and a hydraulic actuator for displacing the synchronizer. The actuator includes a cylinder and a piston which is displaceable within the cylinder delimiting first and second chambers. The volume of the first chamber is smallest when the actuator is in the first engaged position and the volume of the second chamber is smallest when the actuator is in the second engaged position. The piston further delimits at least a third chamber within the cylinder.