The present invention provides a method of controlling input torque of a powered vehicle. The vehicle includes a transmission having an input shaft, an output shaft, and a countershaft. The method includes providing input torque to the input shaft, determining a rotational acceleration of the countershaft, and measuring vehicle speed. The method also includes determining a threshold based on the measured vehicle speed. The measured countershaft acceleration is compared to the threshold and the input torque is controlled based on the result of the comparison.