I have a troy-Bilt TB635EC and the pull string does not engage. I took it apart and one of the Metal pawls fell out and the other is missing. I am looking for 1-metal pawl and 2 of the c-clips. All I can find online are the plastic ones and I read that the metal ones and the plastic ones are not interchangeable? Can someone help? I do not want to have to buy a new Oil Pan assy. Thanks!