Hi, I have a vertical rc katana with the motor and gear box that they offered. I don't know exactly what it is. The gear box is a 5:1 MPJet gear box, but I don't know what the motor is, I think it is a 280. I an having trouble with the pinion gear not staying tight on the motor shaft. I used the glue that came with the new gear box, the original one that came with the airplane was stripped out, and it doesn't stay on. I has come loose twice after a couple of flights. What can I do to keep this pinion gear from spinning on the motor shaft.

John