you mean the rotor belt drive shaft? you have to completely take the frame apart to get it...well you can cheat, and loosen most of the screws, and remove the screws in the rear half completely, and pry it slightly and get it out, but i do not recommend that...its a fun little part to swap out, you get to get and dirty with your helicopters parts if you havent before...

basically your going to strip everything off the frame, servos, motor, esc, rx, gyro, head assembly, tail shaft, skids....