Play animation when 2d character hits collider.

Hello everyone, I am trying to play a animation when the character hits a box that is pushable, but thus far without succes. I have tried the play animation, but that didn't work :(

This script is attached to the Player, and the object to push is cube with a rigidbody.

In the animator I have push animation without any transitions to it.

I hope someone can help me out.

 #pragma strict
 
 // this script pushes all rigidbodies that the character touches
     var pushPower = 2.0;
     function OnControllerColliderHit (hit : ControllerColliderHit) {
         var body : Rigidbody = hit.collider.attachedRigidbody;
         // no rigidbody
         if (body == null || body.isKinematic)
             return;
             
         // We dont want to push objects below us
         if (hit.moveDirection.y < -0.3) 
             return;
         
         // Calculate push direction from move direction, 
         // we only push objects to the sides never up and down
         var pushDir : Vector3 = Vector3 (hit.moveDirection.x, 0, hit.moveDirection.z);
         // If you know how fast your character is trying to move,
         // then you can also multiply the push velocity by that.
         
         // Apply the push
         body.velocity = pushDir * pushPower;
         
         Animation.Play("push");
     }