After installing the tail boom with tail drive and then then main shaft, I discovered a gear stripping sound when turning the main gear. Using a supereyes USB microscope, I could see the tail drive gear(front drive drive gear) does not mesh with the autorotation gear (directly under the main drive gear). I made this video to show Hobbyking as part of my RMA process. I have not flown the heli as I have not completed the build. I have not modified the heli in any way. Without buying new parts, does anyone know a fix?