Character wont slide

I am new to unity and making scripts but I am trying to make my character slide down terrain if the angle is too steep. I am not getting any errors but it wont slide at all. Here is my script so far.

var slideDirection : Vector3; //direction of player slide var moveDirection : Vector3 = Vector3.zero; var canAngleSlide : boolean = true; var speedSlide : float = - 0.0; var moveSpeed : float = - 0.0; var slideControllableSpeed : float = 5.0; //speed at where player still has control var slideThreshhold : float = 0.88; //amount of angle for when the player slides var slideTag : String = "slide"; //the tag for when the player will slide @script RequireComponent (CharacterController) function Start () {

 }            

function Update () {

}

function AngleSlide(){ if (canAngleSlide) //toggle can angle slide { slideDirection = Vector3.zero; //
var hitInfo : RaycastHit; //store hit information

     if (Physics.Raycast(transform.position, Vector3.down, hitInfo))                 //cast a ray and find objects position and what it hit
     {
         if(hitInfo.collider.tag != slideTag)                                        //if the collider tag name is tagged with slide then exit out
         {
             return;                                                                 //return home
             }
             if (hitInfo.normal.y < slideThreshhold)                                  //if our normal direction on that slope is lessthen slide threshhold
             {
                 slideDirection = new Vector3(hitInfo.normal.x, 0, hitInfo.normal.z);//the direction for the player to slide, y is set to 0 to keep play
             }
         }
         if (slideDirection.magnitude < slideControllableSpeed)                      //checks against slide speed, if less then allow some control
         {
                 moveDirection += slideDirection;                                    //this allows for a bit of jerky movement cleanup
         }
         else 
         {
             moveDirection = slideDirection;                                         //force the slide to go straght down based on slide direction
         }
         if (slideDirection.magnitude > 0)                                           //if player is sliding
         {
             moveSpeed = speedSlide;                                                 //move player down at slide speed
         }
     }
 }