Hydraulic circuit for actuation of an automated vehicle transmission

An automatic vehicle gearbox has a clutch control unit (12), a gearbox engagement/disengagement unit (14) and a gearbox selection unit (16). A hydraulic pressure generator (10) supplies a two position valve (26) on the gearbox selector unit and also the clutch control unit via a three position valve (18) but the two two-position valves (30,32) which control gearbox engagement/disengagement are separately supplied