A gear mechanism with at least a flange for the adaptation of the gear mechanism to a drive component and with at least one ring gear, which is firmly connected on the gear side to the flange. The flange presents at least a radial flange bore, the ring gear presents at least a radial ring gear bore, and a pin is led through a pair consisting of such a radial flange bore and such a radial ring gear bore, and in the process the flange and the ring gear are braced firmly against each other. The flange bore and the ring gear bore may be arranged with partial overlap in the axial direction and simultaneously partial mutual offset by an offset difference.