OnCollisionEnter2D Child to Parent

First of all, I am a newbie creating a 2d platformer...

When I hit "J" the player can push,pull, carry (made the box a child to parent player) the box when collide and "K" to release it. The problem is when i first collide with the box and press "J" nothing happens, I need to move my player a little distance away from the box and collide again to make it happen...

What I need to know is to how the player collide with the box first and when I hit "J" the box automatically becomes the child without moving far away first. Any ideas? sorry

Here are my 2 scripts

 using UnityEngine;
 using System.Collections;
 
 public class PlayerController : MonoBehaviour {
     public float jumpHeight = 10;
     public float moveSpeed = 3;
     private PushPull pushpull;
     public Transform groundCheck;
     public float groundCheckRadius;
     public LayerMask whatIsGround;
     private bool grounded;
     private bool doubleJumped;
 
     // Use this for initialization
     void Start () {
         pushpull = new PushPull();
     }
 
     void FixedUpdate()
     {
         grounded = Physics2D.OverlapCircle (groundCheck.position, groundCheckRadius, whatIsGround);
     }
     
     // Update is called once per frame
     void Update () {
         if (grounded)
             doubleJumped = false;
 
         if (Input.GetKeyDown (KeyCode.Space) && grounded ) {
             GetComponent<Rigidbody2D>().velocity = new Vector2 (GetComponent<Rigidbody2D>().velocity.x, jumpHeight);
             Jump ();
         }
 
         if (Input.GetKeyDown (KeyCode.J) && grounded ) {
             pushpull.isAction(1);
 
         }
         if (Input.GetKeyDown (KeyCode.K) && grounded ) {
             pushpull.isAction(0);
             
         }
 
     
         if (Input.GetKey (KeyCode.D)) {
             GetComponent<Rigidbody2D>().velocity = new Vector2 (moveSpeed, GetComponent<Rigidbody2D>().velocity.y);
         }
         if (Input.GetKey (KeyCode.A)) {
             GetComponent<Rigidbody2D>().velocity = new Vector2 (-moveSpeed, GetComponent<Rigidbody2D>().velocity.y);
         }
     }
 
     public void Jump()
     {
         GetComponent<Rigidbody2D>().velocity = new Vector2 (GetComponent<Rigidbody2D>().velocity.x, jumpHeight);
 
     }
 }

 
 
 using UnityEngine;
 using System.Collections;
 
 public class PushPull : MonoBehaviour {
     public GameObject player;
     private static int isPullPush = 0;
 
     public int isAction(int actionSignal)
     {
         isPullPush = actionSignal;
         Debug.Log (isPullPush);
         return isPullPush ;
 
     }
 
 
     // Use this for initialization
     void Start () {
 
     }
     
     // Update is called once per frame
     void Update () {
         if(isPullPush == 0)
         {
             this.gameObject.transform.parent = null;
         }
 
     }
 
 
     void OnCollisionEnter2D(Collision2D coll){
 
         if(coll.gameObject.name=="Player")
         {
             this.gameObject.transform.parent = player.transform;
         }
 
 
 
     }
 
 }