CPC F16H 61/12 (2013.01) [F16H 61/0025 (2013.01); F16H 61/0276 (2013.01); F16H 61/30 (2013.01); F16H 61/682 (2013.01); F16H 2061/1264 (2013.01)] | 20 Claims |
1. A transmission comprising:
an input shaft;
an output shaft;
a plurality of shift elements engageable in sets to create a plurality of power flow paths between the input and output shafts at different speed ratios;
a hydraulic system in fluid communication with the shift elements and including at least one electrohydraulic valve configured to control fluid pressure to at least one of the shift elements; and
a controller in communication with the at least one valve and programmed to, during a shift of the transmission:
command a series of first pressures to a first of the valves associated with an oncoming one of the shift elements while an off-going one of the shift elements is engaged,
command a series of second, higher pressures to the first valve for a duration of time responsive to an expected ratio change between the input and output shafts not commencing and the off-going shift element slipping, and
command a series of pressure pulses, according to a duty cycle, to the first valve responsive to expiration of the duration of time and the expected ratio change not commencing.
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