Transmission Input/Output Sensors

Transmission input/output sensors calculate the transmission’s actual gear ratio during usage. Typically, two sensors communicate the transmission data to the vehicle's powertrain control module. The first sensor, referred to as the input sensor, monitors the speed of the transmission’s input shaft. The second sensor is the output sensor, which monitors the output shaft speed. 

How to Install a Transmission Input/Output Speed Sensor on a Dodge, Chrysler, Plymouth 2.7L Engine