a braking effect can be attained alternatively or additionally in a hybrid vehicle by means of recuperation . this can occur for instance by operating an electric machine and charging a battery associated with it . coupling of flywheels can also take place alternatively or additionally . in particular , with commercial vehicles , also active transmission brakes can be used alternatively or additionally . the failure of a transmission actuator controlled by a control device or the failure of the control device itself can constitute the defect of the transmission . a transmission actuator can be operated electrically , hydraulically , pneumatically or in a similar manner and in turn actuate an automated manual shift transmission , a parallel shift transmission like twin - clutch transmission or other power shift transmission or transmission shifting under gear rattle . the transmission actuator can hence incorporate a linear - actuated controller drum or a shift shaft that is movable in select and shift direction , which engages with corresponding shift geometries like shift guides , selector forks and sleeves . fig1 is a schematic representation of parallel shift transmission 10 . a defect in the transmission for instance can cause an engaged gear not to be disengaged . under certain circumstances this leads to high rotation speed stress on the transmission or clutch components , which can be damaged by this , in that , they burst . for instance , a blocked gear 12 in a partial drive train 14 of a parallel shift transmission 10 with a corresponding ratio , the transmission input shaft 16 of this partial drive train , when the other partial drive train 18 is operated with a gear 20 with a higher ratio , is accelerated such that the friction clutch 22 assigned to partial drive train 14 suffers damage . if the ratios of the two affected gears differ by factor two , for instance , the speed of the transmission input shaft 16 will be doubled by the blocked gear . due to braking of the automatic brake system when a transmission defect is detected , immediate intervention in the speed of the motor vehicle can occur independently of the prevailing torque of the internal combustion engine and excess speeds can be caused in the transmission even with an open clutch between the internal combustion engine and the transmission and / or on inclines . in addition , the prevailing torque of the internal combustion engine in the case of the defect on the transmission can be reduced by an intervention in the control unit of the internal combustion engine . a braking effect can be attained advantageously through recuperation in hybrid vehicles . this can occur by operating an electric machine and charging a battery associated with it . alternatively or additionally , one or several flywheels can be coupled advantageously for the purpose of recuperation . active transmission brakes can also be used advantageously to obtain a braking effect . in motor vehicles with an electronic stabilization program ( esp ) the latter can be used advantageously as an automatic brake system . by means of the electronic stabilization program , individual wheels can be retarded specifically so that when a transmission defect occurs the motor vehicle can be retarded immediately without safety losses even when cornering . thereby , the transmission status can be transmitted advantageously via a communication device , for instance can - bus to a control device of the automatic brake system , for instance to the esp - control device . if transmission status is not transmitted , the brake system can be activated because , in this case , the control device of the transmission may have failed completely and thus the control of the transmission no longer takes place in case a gear is selected . the motor vehicle can be retarded to a suitable speed of the motor vehicle despite a defect of the transmission . furthermore , further increase of the speed , for instance , downhill can be prevented . the retardation to a preselected speed can be predetermined depending on a gear selected in the transmission . the control device computes a suitable speed from a transmission status that contains the gear information , which is not harmful to the drive train in the presence of the defect , and retards the vehicle to the default speed . alternatively , a transmission status can be transmitted to the control device of the brake system , which contains information of a limit speed already computed by the transmission control unit , thus which is not harmful to the transmission or to the clutch assigned to the latter . the control device of the brake system hence retards the motor vehicle to this speed , at least for so long until the defect is eliminated or a workshop is visited .