A method for estimating transmission input torque is provided. The method includes identifying a plurality of measurable characteristics that influence transmission input torque. Thereafter, transmission input torque values are measured on a sample powertrain operating at a plurality of different combinations of the measurable characteristics. A look-up table including the measured input torque values corresponding to each combination of the measurable characteristics is established and saved onto a vehicle memory device. The vehicle is configured to monitor the status of the measurable characteristics during operation. At any given time, the vehicle can retrieve the measured transmission input torque value corresponding to the status of the monitored measurable characteristics wherein the measured transmission input torque value provides an estimate of the transmission input torque of the vehicle.