The FN4A-EL ( 4-speed ) transaxle has two speed sensors an Input Turbine Speed Sensor ( TSS ), mounted on top and a Vehicle Speed Sensor ( VSS ) mounted towards the lower right rear. On the contrary, the FS5A-EL (5-speed) transaxle has three speed sensors: the Intermediate Shaft Speed (ISS) sensor and the TSS at the top, and the VSS is also located at the bottom left rear. Replacement To remove and install the VSS, place the vehicle on jackstands, loosen the engine under-cover, unhook the electrical connector, and detach the mounting bolt to remove the VSS, and discard the old O-ring and use a new one during installation. In other sensors, disconnect the negative battery terminal, battery, battery tray, upper engine cover, electrical connector with the sensor, mounting bolt, and sensor and again discard the old O-ring and replace it with a new one. The single speed sensor is on the top of the manual transaxle.