A parking brake system for use with a transmission of a work vehicle, the parking brake system comprising: a braking mechanism housed within the transmission; and a brake actuator positioned outside the transmission, the brake actuator being coupled to the braking mechanism to allow the braking mechanism to be actuated between an engaged state and a disengaged state, the brake actuator comprising: a housing extending between a first end and a second end, the housing at least partially defining a rod-side chamber, a secondary chamber and a piston-side chamber extending between the rod-side and secondary chambers; a primary piston positioned within the housing between the piston-side and rod-side chambers, the primary piston movable between a first position at which the braking mechanism is actuated to the engaged state and a second position at which the braking mechanism is actuated to the disengaged state; a rod extending partially within the rod-side chamber and including an internal end coupled to the primary piston and an external end positioned outside the housing; a spring housed within the rod-side chamber so as to be engaged between the piston and the first end of the housing; characterised by a secondary piston at least partially housed within the secondary chamber, the secondary piston extending between a proximal end positioned at or adjacent to the primary piston and a distal end positioned opposite the proximal end, the secondary piston being configured to apply a force against the primary piston when fluid is supplied within the secondary chamber at the distal end of the secondary piston in order to move the primary piston from the first position to the second position. a braking mechanism housed within the transmission; and a brake actuator positioned outside the transmission, the brake actuator being coupled to the braking mechanism to allow the braking mechanism to be actuated between an engaged state and a disengaged state, the brake actuator comprising: a housing extending between a first end and a second end, the housing at least partially defining a rod-side chamber, a secondary chamber and a piston-side chamber extending between the rod-side and secondary chambers; a primary piston positioned within the housing between the piston-side and rod-side chambers, the primary piston movable between a first position at which the braking mechanism is actuated to the engaged state and a second position at which the braking mechanism is actuated to the disengaged state; a rod extending partially within the rod-side chamber and including an internal end coupled to the primary piston and an external end positioned outside the housing; a spring housed within the rod-side chamber so as to be engaged between the piston and the first end of the housing; characterised by a secondary piston at least partially housed within the secondary chamber, the secondary piston extending between a proximal end positioned at or adjacent to the primary piston and a distal end positioned opposite the proximal end, the secondary piston being configured to apply a force against the primary piston when fluid is supplied within the secondary chamber at the distal end of the secondary piston in order to move the primary piston from the first position to the second position. a housing extending between a first end and a second end, the housing at least partially defining a rod-side chamber, a secondary chamber and a piston-side chamber extending between the rod-side and secondary chambers; a primary piston positioned within the housing between the piston-side and rod-side chambers, the primary piston movable between a first position at which the braking mechanism is actuated to the engaged state and a second position at which the braking mechanism is actuated to the disengaged state; a rod extending partially within the rod-side chamber and including an internal end coupled to the primary piston and an external end positioned outside the housing; a spring housed within the rod-side chamber so as to be engaged between the piston and the first end of the housing; characterised by a secondary piston at least partially housed within the secondary chamber, the secondary piston extending between a proximal end positioned at or adjacent to the primary piston and a distal end positioned opposite the proximal end, the secondary piston being configured to apply a force against the primary piston when fluid is supplied within the secondary chamber at the distal end of the secondary piston in order to move the primary piston from the first position to the second position.