Deere & Company

Russell Dee Taylor

Clayton George Janasek

Richard Marvin Sparks

A method of controlling, in response to a shift command, a commanded shift of a powershift transmission of an engine-driven vehicle includes monitoring speeds transmission component selected according to the commanded shift and monitoring a speed ratio therefrom. If the input section will speed up during the commanded shift, the speed clutches are swapped, and then the output clutches are swapped when the monitored speed ratio matches a stored speed ratio. Also, the input speed of an input shaft of the transmission is monitored, and the pressure of the off-going output clutch is controlled to limit the deceleration of the input shaft speed to desired limits. If the input section will slow down during the commanded shift, the output clutches are swapped, and then the speed clutches are swapped when a monitored speed ratio matches a stored speed ratio. If a particular shift requires swapping of only speed clutches, then a speed ratio is monitored for the pair of the speed clutches to be swapped. If the input section will speed up or slow down during the commanded shift, the pair of speed clutches are swapped, and the monitored speed ratio is compared to a predetermined stored speed ratio value to determine when swapping of the speed clutches is completed, and after the speed clutches are swapped, one of the output clutches is fully pressurized to complete the shift.

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Manhattan, KS, United States of America

Russell Dee Taylor