ORIGINAL: AffordableRC

If you have a 2 speeds transmission make sure that both gears are meshed correctly. It is possible to have it at an angle so one gear feels like its meshed fine and the other is too tight. The paper trick should prevent this but just double check. Make sure once you get it back together and meshed correctly that you feel the amount of play in the gears for future reference. Once you know what it should feel like then you wont need to hassle with the paper.