The invention relates to a transmission drive assembly (10) having a drive motor (11) the drive shaft (23) of which protrudes with a portion (25) thereof into a transmission housing (12), wherein the drive shaft (23) is arranged on the side facing the transmission housing (12) in a bearing (32) which is held in a form-fit or force-closed manner in a substantially sleeve-shaped holding element (35; 65) which is arranged in a holding fixture (27) of the transmission housing (12). According to the invention, in an installation position for introducing and positioning the holding element (35; 65) in the holding fixture (27) of the transmission housing (12), the holding element (35; 65) is positioned in a first axial end position defined by an abutment element (30) of the drive motor (11), and, in an end position of the drive shaft (23) in the transmission housing (12), the holding element (35; 65) can be slid by means of a sliding element (47; 61; 62, 63) on the drive shaft (23) into a second axial end position which is axially remote from the at least one abutment element.