| 摘要 |
In a hydraulic control apparatus for a vehicular automatic transmission (10), if it is determined that there is a failure that may cause tie-up in an automatic transmission (10), communication is provided between a first output port (38c) and a first drain port (38a) in a switching valve (36). As a result, a hydraulic frictional engagement device, which should be disengaged when there is a failure, is disengaged. Also, a specific shift speed is achieved by controlling the switching valve (36). Therefore, it is not necessary to select a shift speed that is achieved on the condition that the hydraulic frictional engagement device, which should be disengaged when there is a failure, is engaged. Thus, it is possible to prevent a shift that may impair driveability when there is a failure that may cause tie-up in the automatic transmission (10). |
