Wheel Collider Behaving a bit Strange in unity 5. Any ideas?

Hello! I just got unity5 and i straight off went to make a vehicle to test the new physics engine. When i went to start coding the car. I hit Play and the car landed. and it Just went like freakin free-style all over the place...

Any Ideas is to what could of went wrong?

here's my code:

 public WheelCollider pivotFL;
     public WheelCollider pivotFR;
     public WheelCollider pivotRL;
     public WheelCollider pivotRR;
     public Transform meshFL;
     public Transform meshFR;
     public Transform meshRL;
     public Transform meshRR;
 
     Rigidbody car;
 
     void Start()
     {
         car = GetComponent<Rigidbody>();
     }

This is All i did...

Any help is sooo welcome :D Thanks again!