Determining oncoming clutch pressure in a transmission

Clutch pressure of an oncoming clutch may be determined during an upshift in an automatic transmission by determining when offgoing and oncoming clutches of the transmission near a speed synchronization point. Aboard a vehicle, proportional-integral-derivative (PID) feedback control logic of for the oncoming clutch may be activated via a controller. The controller and the activated PID logic may be used to introduce a calibrated slip error between the rotational speeds of the offgoing and oncoming clutches. Engine speed is then held in a calibrated flare using the PID logic. Oncoming clutch pressure is recorded during the duration of the calibrated flare, and a control action is executed with respect to the transmission using the recorded oncoming clutch pressure, e.g., using recorded PID gains and/or a pressure/torque relationship of the oncoming clutch. A vehicle having an engine, transmission, and controller may use the controller to execute such a method.