Jumping with Character Controller?!

So I am currently developing a parkour system for my game. I have used the Unity default First Person Controller for almost a year now, and I recently realized that I had to make my own character controlling system for my parkour system. Basically, I am using a Character Controller to do this. Here is the code that I am using: var speed : float = 6.0; var jumpSpeed : float = 100.0; var gravity : float = 25.0; private var moveDirection : Vector3 = Vector3.zero;

 function PlayerController(){
     var controller : CharacterController = GetComponent(CharacterController);
     moveDirection = Vector3(Input.GetAxis("Horizontal"), 0, Input.GetAxis("Vertical"));
     moveDirection = transform.TransformDirection(moveDirection);
     moveDirection *= speed;
     if (controller.isGrounded) {
         if (Input.GetButtonDown ("Jump")) {
             moveDirection.y = jumpSpeed;
         }
     }
     moveDirection.y -= gravity * Time.deltaTime;
     controller.Move(moveDirection * Time.deltaTime);
 }

Now this works fine in terms of moving, but for jumping, not so much. I want my game to have somewhat realistic gravity, so I turned it up in the Unity Editor to 125. This makes a pretty realistic gravity effect, but the jumping screws up then. Basically, I would have to put the jumpSpeed to like 100 for the character to actually move up, and when it does it almost teleports up and then falls down. What I need is a good jumping fade, like the First Person Controller that Unity comes with.

Any help is appreciated, - william9518