THe top part of the inner shaft broke on my cx2 and i replaced it with the metal upgrade one, but the gear back on the shaft, and it flies nothing like it used to. I used to be able to take it up and hover with no problems but now when i get to about half throttle, it flies forward and to the left. I have set the trims as far as they will go and it still seems to have a mind of its own. Any ideas on what could be wrong?