Gearbox with two component transmissions each having a power-shift clutch

A change-speed gearbox, for transverse installation in a front wheel drive vehicle, comprises two power-shift clutches K1, K2 each having a concentric intermediate shaft 14, 15. Intermediate shaft 14 is connected to layshafts 16, 17 via a component transmission. 12 having gear stages ZIII*/III, ZV, ZI and ZIV*, while intermediate shaft 15 is connected to layshafts 16, 17 via component transmission 13 having gear stages ZVI, ZR, ZII and ZIV. To allow double shifts, eg skipping gears, the component transmissions 12, 13 are provide with gear stages ZIV*, ZIV, having equal transmission ratios, which are mounted on layshaft 17. Gear stages ZIII*/III and ZIV* share a common free gear 20 which is coupled to the intermediate shaft 14 by an gear clutch s-III and to the intermediate shaft 15 by a gear clutch s-III*/IV*. Gear 20 meshes with a gear 22 freely mounted on layshaft 16 and with gear 21 freely mounted on layshaft 17. Gear clutches s-III*/III and s-IV connect gears 22, 21 to the layshafts 16, 17 respectively. Several methods of changing gear involving overlap control of the power-shift clutches are also disclosed.