In a method of operating a drive train of a motor vehicle including a drive motor with a multi-unit transmission including an unsynchronized main transmission and a synchronized output drive unit, wherein, for performing a shift in the unsynchronized main transmission, a speed synchronization is carried out by means of the drive motor for the engagement of a target gear and, in an emergency mode of the drive motor, a clutch arranged between the drive motor and the main transmission is disengaged, the output gear unit is placed into neutral, the target gear is engaged, the output drive unit is placed into a drive position and the clutch is at least partially engaged.