Method for controlling a power transmission

The method involves operating an electric machine as a generator and a motor to speed-up a process of shift operation and to attenuate torque and speed surges during the shift operation. The electric machine is drivingly connected with a driveshaft of a combustion engine. An automated friction clutch is arranged between the driveshaft and an input shaft (GE) of an automated gearbox such that the shift operation of the gearbox occurs in connection with control of the combustion engine when the friction clutch is partially and/or temporarily closed.