Patent ID: 7442148

Claim:
A method for operating the drive train of a motor vehicle, having a prime mover, an automatic transmission, a power divider actuated by external force and not power-shiftable, and at least one control device for activating the prime mover, the automatic transmission and the power divider; wherein: a shift is executed by the control device in the presence of a shift requirement for the power divider; before the commencement of the shift, the control device reduces torque at shifting members involved in the shift by interrupting the force flux between the prime mover and power divider, by the opening a clutch in the automatic transmission; after completion of the shift, the control device restores the force flux by closing of said clutch and permitting a torque again at said shifting members; the motor vehicle has an activatable brake system; the control device monitors at least one of i) speed of the motor vehicle and ii) variables derived from the vehicle speed during a shift of the power divider; the control device activates the brake system as a function of the result of the monitoring; and, in the presence of a shift requirement, the control device calculates a rotational speed of the prime mover after the shift and carries out a shift in the automatic transmission or suppresses the shift requirement as a function of the calculated rotational speed.