A suspension system for use with a vehicle including an axle tube, an internal tube and a locking structure. The axle tube is adapted to be attached to the vehicle. The internal tube assembly has an inner member with a first end and a second end. A locking structure is formed integrally at the second end with the inner member. The locking structure has a locking shape that allows the internal tube assembly to be inserted into the axle tube when the locking structure is rotated to a non-operational position. The internal tube assembly is prevented from being removed from the axle tube when the internal tube assembly rotates between jounce and rebound positions when the suspension system is operational.