A system for determining when a selectable one-way clutch has mechanically released includes an update timer identifying if each of a converter model engine torque, a transmission input torque, and atorque converter slip are positive for a predetermined period of time. An SOWC slip value is calculated using an output signal from each of: at least one transmission internal speed sensor producing an output signal representative of a speed of an internal component of a transmission; and at least one transmission output speed sensor producing an output signal representative of a speed of an output of the transmission. An SOWC released signal is issued if either all of the measured converter model engine torque, the measured transmission input torque, and the measured torque converter slip arepositive for at least the predetermined period of time, or the calculated SOWC slip value is greater than a predetermined threshold.