1. Method for controlling torque converter slip in a powertrain comprising an engine, a transmission, and a torque converter located between the engine and the transmission, the method comprising: monitoring slip in the torque converter; in response to an unintended rapid increase in slip from a desired non-zero slip speed while operating the torque converter in a controlled slip mode, increasing command pressure of a torque converter clutch of the torque converter to reduce the slip back to the desired non-zero slip speed; statistically analyzing the monitored slip to determine a likely condition of the torque converter; and utilizing the likely condition of the torque converter to control the torque converter slip comprising modulating a command pressure of a torque converter clutch of the torque converter to one of recover from a crashed condition or avoid the crashed condition, the crashed condition corresponding to a zero slip speed.