Gear drive unit with a load torque lock

Gear drive unit (10), in particular a window lifter drive, with an electric motor (14) driving a transmission (30), and with a load torque lock (44) introduced by a driven-side coupling element (42) torques (86) blocks, wherein the load torque lock (44) comprises a wrap spring (54) which is arranged on / in a non-rotatable shaft (50, 52) and engages in a drive end of a rotor shaft (16) of the electric motor (14) driven gear wheel (40).