A road simulation test system and method for testing torsional strain input to an axle assembly having an input shaft and a suspension system, including a torque input module configured to apply rotary torque to the axle assembly. The torque input module includes a rotary actuator, a torsional load cell, a drive shaft connection portion, and a controller in communication with the rotary actuator and the torsional load cell, wherein upon receipt of an instruction from the controller, the rotary actuator is configured to rotate the input shaft to apply the rotary torque to the axle assembly, and as the rotary actuator rotates the input shaft, a signal indicative of a torsional load is communicated by the torsional load cell to the controller to monitor the rotary torque applied to the axle assembly.