Direct-fit replacement provides proper fit, form, and function. Quality-engineered replacement for damaged OE units with rotted or torn diaphragms, which cause actuators to fail, prevent hubs from engaging, and cause vehicles to be stuck in 2WD mode. Quality-designed vacuum-operated diaphragm allows axles to engage properly during 4WD operation. All TechSmart(R) parts meet or exceed OE performance, providing today's technician with the quality parts needed to get the job done right, the first time.