Patent ID: 7278953

Claim:
A method of shifting a powershift transmission having an off-going clutch and an on-coming clutch, the method comprising: when a shift is commanded, rapidly reducing off-going clutch pressure, P-off, to a pressure which is slightly higher than a pressure (Predicted Off Slip Pressure) at which the off-going clutch would start to slip, and rapidly increasing on-coming clutch pressure P-on to a pressure that is slightly lower than a pressure (Predicted On Slip Pressure) at which the on-coming clutch would transmit torque; thereafter, gradually decreasing P-off and gradually increasing P-on until slipping of the off-going clutch is detected; thereafter, gradually and more slowly decreasing P-off and gradually and more slowly increasing P-on until the oncoming clutch begins to carry torque previously carried by the off-going clutch; and thereafter more rapidly decreasing P-off to reservoir pressure, and more rapidly increasing P-on to a full on pressure.