...
public float pushForce = 3.0f;   
...
void OnControllerColliderHit(ControllerColliderHit hit) {
   _contact = hit;

   Rigidbody body = hit.collider.attachedRigidbody;
   if (body != null && !body.isKinematic) {
      body.velocity = hit.moveDirection * pushForce;   
   }
}
...
