Patent ID: 7731630

Claim:
A method of calibrating a hydraulic transmission for a machine, the transmission being driven by an engine and having an input shaft and an output shaft and a plurality of selectable gear ratios for altering a transmission ratio between the input shaft and output shaft, and a plurality of hydraulic clutches, each operable to select one of the plurality of selectable gear ratios when actuated, the method comprising: initiating at least one shift between a first gear ratio selected by a first one of the hydraulic clutches and a second gear ratio selected by a second one of the hydraulic clutches during operation of the machine; determining a pulse width for a fill pulse usable to fill the second one of the hydraulic clutches based on torque transfer characteristics of the transmission during a shift; determining a hold level current for the second one of the hydraulic clutches based on a duration of a shift; and executing a subsequent shift between the first and second gear ratios by applying a fill pulse of the determined pulse width to fill the second one of the hydraulic clutches and then applying the derived hold level current, wherein the step of determining a pulse width for a fill pulse usable to fill the second one of the hydraulic clutches further includes determining a plurality of pulse widths respectively usable within each of a plurality of groups of engine speed ranges and wherein the step of determining a hold level current for the second one of the hydraulic clutches further includes determining a plurality of hold level currents respectively usable within each of the plurality of groups of engine speed ranges.