A method of controlling an automated transmission with positioning cylinders (6, 8, 20) controlled by shift valves or venting valves (10, 12, 16, 18, 22, 24). At least one cut-off valve (4) is positioned in front of the shift or venting valves and a control device controls the valves while pressure pipes, which follow the cut-off valve (4), are connected with one another following the cut-off valve (4). Due to the fact that the cut-off valve (4), for reasons of design simplicity and cost, is generally designed as a simple 2/2 way valve which only allows pressure increase but not pressure reduction, the method provides control of the shift valves or ventilation or venting valves (16, 18), of a non activated positioning cylinder (8), so that the pressure pipe system is connected with an outflow pipe (14) for a pressure reduction in the pressure pipe system (30, 32, 34).