Abstract: A method for controlling a transmission includes using actuation of a button of a shift module to produce a signal representing a desired gear, using the signal and a second signal commanding a park range to determining a priority range, using a shift mechanism to attempt engagement of the transmission in the priority range, and if the priority range is park and park is not engaged, engaging a park brake.

Abstract: A method for controlling a transmission gear change to a desired gear includes disengaging an offgoing transmission control element, changing engine speed to a synchronous speed of the desired gear, decreasing engine output torque, and engaging an oncoming transmission control element.

Abstract: A park mechanism includes a cam pivotal between Park and not-Park ranges, including a radial outer surface formed with angularly spaced lobes, a roller urged by a spring into contact with the outer surface, a park spring urging the cam toward the Park-range, a power source for pivoting the cam, and a pawl actuated by cam movement into a Park state and a not-Park state.

Abstract: A method for controlling a transmission gear change to a desired gear includes disengaging an offgoing transmission control element, changing engine speed to a synchronous speed of the desired gear, decreasing engine output torque, and engaging an oncoming transmission control element.

Abstract: A method for controlling a transmission includes using actuation of a button of a shift module to produce a signal representing a desired gear, using the signal and a second signal commanding a park range to determining a priority range, using a shift mechanism to attempt engagement of the transmission in the priority range, and if the priority range is park and park is not engaged, engaging a park brake.

Abstract: A diagnostic strategy for an automatic transmission having electronic shift control solenoids for controlling application and release of clutches and brakes during the establishment and disestablishment of torque ratios in multiple-ratio gearing for the transmission wherein provision is made for developing diagnostic data that detects failure modes due to a faulty shift solenoid by using predetermined failure modes stored in the RAM portion of a microprocessor and comparing those known failure modes to the actual performance of the shift solenoids.

Abstract: An automatic transmission having multiple-ratio gearing, fluid pressure-operated clutches and brakes adapted to establish and to disestablish multiple torque ratios and electronic shift control solenoids that can be energized and de-energized under the control of an electronic microprocessor that senses transmission operating variables, and a control strategy inherent in the microprocessor that uses predetermined failure modes to perform functional testing on the shift solenoids without special hydraulic and electronic hardware for developing the diagnostic information that detects shift solenoid failures or malfunctions.

Abstract: In an electronically controlled transmission adapted to control operation of a torque converter clutch in softlock and hardlock modes, a test to determine whether the clutch is operating with an acceptable slip magnitude in a control region or whether it is operating with a high level of slip or instability outside the control region. The test distinguishes periods of instability associated with deterioration of the clutch from transients associated with normal operating conditions and background noise. An instability counter, interval clock and warm-up cycle counter are used to determine an appropriate point for discounting prior events and reentering the control test. Continuous slip mode of operation of the clutch is disabled entirely after a predetermined number of verified unstable events have occurred.