Input Shaft (Mainshaft) Speed Sensor Replacement

Raise the vehicle on a lift, or apply the parking brake, block both rear wheels, and raise the front of the vehicle. Make sure it is securely supported.
Remove the front undercover (A) and the splash shield (B).

Fig 1: Locating Front Undercover And Splash Shield With Torque Specifications
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Disconnect the input shaft (mainshaft) speed sensor connector, and remove the input shaft (mainshaft) speed sensor (A).

Fig 2: Locating Input Shaft (Mainshaft) Speed Sensor And O-Ring With Torque Specifications
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Apply ATF to a new O-ring (B), and install the O-ring over the input shaft (mainshaft) speed sensor. Then install the input shaft (mainshaft) speed sensor.
Check the connector for corrosion, dirt, or oil, and clean or repair if necessary, then connect the connector securely.
Install the splash shield and the front undercover.