Patent ID: 8439805

Claim:
An automatic vehicle transmission comprising: a first oil supply unit ( 10 , 110 ) comprising at least one mechanically driven first pump ( 11 ), a second oil supply unit ( 20 ) comprising at least an electrically driven second pump ( 21 ), a valve device ( 14 , 114 ), a clutch system ( 1 ) by which various transmission ratio steps are engagable, a first one-way valve ( 31 ), located between the first oil supply unit ( 10 , 110 ) and a pressure line ( 41 ) for the clutch system ( 1 ), for only permitting oil to flow from the first oil supply unit ( 10 , 110 ) to the clutch system ( 1 ), a second one-way valve ( 32 ), located between the second oil supply unit ( 20 ) and the pressure line ( 41 ) for the clutch system ( 1 ), for only permitting oil to flow from second oil supply unit ( 20 ) to the clutch system ( 1 ), the second oil supply unit ( 20 ) supplying the clutch system ( 1 ) with oil during a first operating condition, and the first oil supply unit ( 10 , 110 ) supplying the clutch system ( 1 ) with oil during a second operating condition.