The invention relates to a gear mechanism comprising at least one drive shaft and at least one output shaft, which enter a gear mechanism housing through a respective opening. The drive shaft and/or the output shaft comprise a magnetically or optically coded section in the region of the respective opening. The coding in said section may be changed by the effect of a torque or a force on the drive shaft or output shaft. Moreover, at least one gear wheel connected to the drive shaft and at least one gear wheel connected to the output shaft are provided that are directly or indirectly engaged with one another. In addition, the gear mechanism according to the invention comprises at least one scanning unit for detecting the magnetic or optical coding of the drive shaft or output shaft in a contact free fashion. The scanning unit is disposed in a housing cover surrounding the magnetically or optically coded section of the drive shaft or output shaft and connected electrically to an analysis unit for detecting an overload of the gear mechanism.