Hydraulic System for a Transmission of a Motor Vehicle

A hydraulic system (4) for a transmission (3) of a motor vehicle (1), comprising:

• a primary system-pressure circuit (16);
• a secondary system-pressure circuit (18);
• a first pump (5) drivable by an engine (2) of the motor vehicle (1) and an electrically drivable second pump (20), the first pump (5) and the second pump (20) each being configured for conveying hydraulic fluid into the primary system-pressure circuit (16) and into the secondary system-pressure circuit (18) so that an intended pressure prevails in the primary system-pressure circuit (16) and in the secondary system-pressure circuit (18);
• liquid retention means (15, 26) configured for preventing a flow of hydraulic fluid conveyed by the second pump (20) from being conducted through the first pump (5) when the first pump (5) is not conveying and the second pump (20) is conveying, and for preventing a flow of hydraulic fluid conveyed by the first pump (5) from being conducted through the second pump (20) when the second pump (20) is not conveying and the first pump (5) is conveying;
• and
• a sailing-mode lubricating valve (22) configured for controlling, by an open-loop system, a flow rate of hydraulic fluid conveyed by the second pump (20) into the primary system-pressure circuit (16) and into the secondary system-pressure circuit (18) such that the intended pressure is set in the primary system-pressure circuit (16) and in the secondary system-pressure circuit (18).