Abstract: In system and method of controlling an automatic transmission that includes a lowest gear-stage friction element and has a lowest gear stage having a largest gear ratio and a gear stage other than the lowest gear stage, the lowest gear stage being established through engagement of the lowest gear-stage friction element, the gear stage other than the lowest gear stage being established while the lowest gear-stage friction element is kept in disengagement, a temperature of working oil in the automatic transmission is sensed, and use of the lowest gear stage is inhibited and use of the gear stage other than the lowest gear stage is allowed when the sensed temperature of the working oil is lower than a first predetermined temperature as a predetermined extremely low temperature at which an engagement failure of the lowest gear-stage friction element is caused.

Abstract: There is provided a control apparatus for a vehicular automatic transmission which reliably inhibits switching between ranges caused by an erroneous operation of a shift lever and enables a vehicle to continue running normally without interfering with the operation of returning the shift lever to a normal position. When the shift lever is switched to a reverse range in a state in which a flag Flag_D_high indicative of a forward high vehicle speed assumes “1”, this operation is determined as being an erroneous operation, and gear shift to a reverse gear position is inhibited from being accomplished. When the shift lever is switched to a forward range in a state in which a flag Flag_R_high indicative of a reverse high vehicle speed assumes “1”, this operation is determined as being an erroneous operation, and gear shift to a forward gear position is inhibited from being accomplished.

Abstract: In system and method of controlling an automatic transmission that includes a lowest gear-stage friction element and has a lowest gear stage having a largest gear ratio and a gear stage other than the lowest gear stage, the lowest gear stage being established through engagement of the lowest gear-stage friction element, the gear stage other than the lowest gear stage being established while the lowest gear-stage friction element is kept in disengagement, a temperature of working oil in the automatic transmission is sensed, and use of the lowest gear stage is inhibited and use of the gear stage other than the lowest gear stage is allowed when the sensed temperature of the working oil is lower than a first predetermined temperature as a predetermined extremely low temperature at which an engagement failure of the lowest gear-stage friction element is caused.

Abstract: There is provided a control apparatus for a vehicular automatic transmission which reliably inhibits switching between ranges caused by an erroneous operation of a shift lever and enables a vehicle to continue running normally without interfering with the operation of returning the shift lever to a normal position. When the shift lever is switched to a reverse range in a state in which a flag Flag_D_high indicative of a forward high vehicle speed assumes “1”, this operation is determined as being an erroneous operation, and gear shift to a reverse gear position is inhibited from being accomplished. When the shift lever is switched to a forward range in a state in which a flag Flag_R_high indicative of a reverse high vehicle speed assumes “1”, this operation is determined as being an erroneous operation, and gear shift to a forward gear position is inhibited from being accomplished.

Abstract: A shift control apparatus is arranged to effect a shift in an automatic transmission by changeover of friction elements to be engaged with disengagement of a disengagement-side friction element and engagement of an engagement-side friction element. A shift controller is configured to detect an end of a loss stroke in the engagement-side friction element, and performs an operation to decrease the disengagement-side working oil pressure at a set gradient and to increase the engagement-side working oil pressure at a predetermined gradient upon detection of the end of the loss stroke in the engagement-side friction element. The predetermined gradient of the engagement-side working oil pressure for the engagement-side friction element is made lower for a low engine load than for a high engine load.

Abstract: A shift control system of an automatic transmission executes an interchange shift by interchanging engagement conditions of first and second friction elements of the automatic transmission. The first and second friction elements are engaged and disengaged according to oil pressures supplied thereto. A controller of the shift control system is arranged to decrease the second oil pressure of the second friction element by a second predetermined gradient and to increase the first oil pressure of the first friction element by a first predetermined gradient after the loss stroke of the first friction element is terminated, and to determine the first gradient such that a difference between a command pressure and an actual pressure of the first friction element is kept substantially constant.

Abstract: As the disengage pressure command value PO lowers and as the engagement pressure command value PC rises, a changeover shift is effected by bringing a disengagement side friction element into disengagement and a disengagement side friction element into engagement. The rising gradient of the engagement pressure command value PC at and after the ON instant t2 of the oil pressure switch, when the engagement side friction element takes the engaging capacity, is made as low as &ggr;1 for a low throttle opening degree but as high as &ggr;2 for a high throttle opening degree, and the lowering gradient of the disengagement side pressure command value PO is also made as small as &bgr;1 at the low throttle opening degree and as large as &bgr;2 at the high throttle opening degree.

Abstract: A shift control system of an automatic transmission executes an interchange shift by interchanging engagement conditions of first and second friction elements of the automatic transmission. The first and second friction elements are engaged and disengaged according to oil pressures supplied thereto. A controller of the shift control system is arranged to decrease the second oil pressure of the second friction element by a second predetermined gradient and to increase the first oil pressure of the first friction element by a first predetermined gradient after the loss stroke of the first friction element is terminated, and to determine the first gradient such that a difference between a command pressure and an actual pressure of the first friction element is kept substantially constant.