A gearshifting unit for a vehicle transmission (6) comprising a main transmission part (10) manually shifted by the vehicle driver using a gearshift lever (16) and one range change group transmission (14) shifted by valves (44, 46). The gearshifts are manually preselectable by the vehicle driver using a gearshift lever (16), the same as a power assistance device (74) for shifting the gear steps in the main transmission part (10) and one electronic control device (20) which actuates the valves (44, 46). In a method for reducing the power assistance, a neutral position is detected in the manually shifting main transmission part (10) and once the neutral position is determined, the gearshift begins in the range change group transmission part (14) and the power assistance is engaged with a delay.