Input Shaft (Mainshaft) Speed Sensor Replacement

Raise the vehicle up 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 transmission undercover (A) and splash shield (B).

Fig 1: Transmission Undercover And Splash Shield With Torque Specification
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Remove the damper from the front subframe.

Fig 2: Damper With Torque Specification
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 3: Input Shaft (Mainshaft) Speed Sensor And O-Ring With Torque Specification
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Install the new O-ring (B) on the new input shaft (mainshaft) speed sensor, then install the input shaft (mainshaft) speed sensor.
Check the connector for rust, dirt, or oil, then connect it securely.
Install the damper on the front subframe.
Install the splash shield and transmission undercover.