Abstract: A failure detecting apparatus for a hydraulic circuit of a gearbox includes an operating-state detector. The operating-state detector is configured to detect an operating state of a subject to be controlled with a control-signal pressure output from a solenoid valve. A current setting device is configured to set an electrical current supplied to a solenoid so as to close an output oil passage when a modulator valve is normal and to open the output oil passage when an open failure occurs in the modulator valve, while the solenoid valve is conductive. A failure determining device is configured to detect a failure of the modulator valve when the operating state of the subject to be detected by the operating-state detector is abnormal after a value of the electrical current to be supplied to the solenoid is set at the current setting device.

Abstract: A failure detecting apparatus for a hydraulic circuit of a gearbox includes an operating-state detector. The operating-state detector is configured to detect an operating state of a subject to be controlled with a control-signal pressure output from a solenoid valve. A current setting device is configured to set an electrical current supplied to a solenoid so as to close an output oil passage when a modulator valve is normal and to open the output oil passage when an open failure occurs in the modulator valve, while the solenoid valve is conductive. A failure determining device is configured to detect a failure of the modulator valve when the operating state of the subject to be detected by the operating-state detector is abnormal after a value of the electrical current to be supplied to the solenoid is set at the current setting device.

Abstract: A shift control system is arranged such that a shift lever 201 is movable to a “P” position, an “R” position, an “N” position, a “D5” position and a “D4” position along a first shift guide path 211, it is movable also from the “D4” position to a “3/M” position along a connection shift guide path 212, and it is movable also along a second shift guide path 213, from the “3/M” position into a direction different from that of the connection shift guide path 212. When the shift lever is shifted to the “D5” position, the transmission is set into an automatic shift control with forward drive speed ratios up to the FIFTH speed ratio. When the shift lever is shifted to the “D4” position, the transmission is set into an automatic shift control with forward drive speed ratios up to the FOURTH speed ratio.

Abstract: A shift control system is arranged such that a shift lever 201 is movable to a “P” position, an “R” position, an “N” position, a “D5” position and a “D4” position along a first shift guide path 211, it is movable also from the “D4” position to a “3/M” position along a connection shift guide path 212, and it is movable also along a second shift guide path 213, from the “3/M” position into a direction different from that of the connection shift guide path 212. When the shift lever is shifted to the “D5” position, the transmission is set into an automatic shift control with forward drive speed ratios up to the FIFTH speed ratio. When the shift lever is shifted to the “D4” position, the transmission is set into an automatic shift control with forward drive speed ratios up to the FOURTH speed ratio.