Im a beginner with rc flying and iv got a trex 100 to learn with. i was flying it today and the Main Drive Gear came loose. iv tried fixing it but no part fits. can any1 post a link to the part i need to fix this??

I had this happen to me. Gently hold top where blades conect and using pencil with eraser to push bottom of gear upwards holding top it should snap back in place. Unless you hit hard just try to get it into proper position. Its kind of built in crash protector for main head gear. Hope this helps. Like I say hard to tell from your picture.

got it fixed i think. thanks Dankar04