Abstract: A transmission gear comprising a fixed gear case, a drive shaft and a driven shaft supported for independent rotation in the gear case and a planetary gear arranged between the drive and driven shafts. The planetary gear comprises a sun wheel that is nonrotatably connected with the drive shaft, a planetary wheel carrier around the sun wheel which is rotated with respect to the sun wheel, at least one planet wheel supported on the planet wheel carrier around the sun wheel and each planet wheel mates with the sun wheel to be rotated thereby. A gear rim rotates with respect to and mates with the planet wheels. An axially displaceable clutch element has a first axial position at which the clutch element couples the planet wheel carrier with the gear case in a torsionally rigid manner and has a second axial position at which the clutch element couples the planet wheel carrier with a driven shaft in a torsionally rigid manner. The clutch element comprises separated but joined together clutch wheels.