I have a fully build A999 trans, we just have made about 15 passes on it. Sometimes when I shift into 1st gear the engagement of the trans does not take place right away. I rev the engine, and like after a second or so the car start moving. I have verified the oil and the trans is full, I thought probably it was low on trans fluid and took time to engage. What can be the cause of of delaying the engagement into 1st gear?