simple rotation question

I have my car moving in a scene in unity but how do I take the Rotation of the car and put it in to the steering wheel ? In maya it would be steeringWheel.rz= car.ry ;

the bigger issue is I'm not seeing where I really specify the steeringWheel or the car or strip out just one of the axis?

var steeringWheel : Transform;
var car : Transform;
function Update () {
    steeringWheel.transform.rotation.z = car.transform.rotation.y;

Drop the steering wheel and car GameObjects in the appropriate Inspector slots.