Unable to AddForce on Navmesh Agent even when Navmesh is off.

have an object that uses a navmesh and follows the player around - no troubles. I want to have this object to "jump" on occasion. I have a Jump() function which temporarily turns the NavMesh off, then adds force. Then I check on collision with the ground to turn the navmesh back on but the force does not seem to have any affect on the object. Code below:

void Jump() {

agent.Stop(true);
GetComponent<Rigidbody> ().AddForce( Vector3.up*5,ForceMode.Impulse);

}




void OnCollisionEnter(Collision otherObject)
{

Debug.Log("hit tag: "+otherObject.gameObject.tag);


if(otherObject.gameObject.tag == "Ground")
{

Debug.Log("Hit the ground");
isJumpingNow=false;
LemmingState=State.FollowPlayer;
agent.Resume();
}

}

 

I did notice that I can addforce on x and z axis but not y.