Speed Sensor Replacement

Disconnect the connectors from the mainshaft and countershaft speed sensors.
Remove the bolt securing the mainshaft speed sensor, then remove the mainshaft speed sensor (A) from the end cover.

Fig 1: Removing Mainshaft Speed Sensor
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Remove the bolt securing the countershaft speed sensor, then remove the countershaft speed sensor (B) from the transmission housing.

Fig 2: Removing Countershaft Speed Sensor
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Replace the O-rings (C) with new ones before installing the sensors.
Install the mainshaft and countershaft speed sensors. When installing sensors, do not allow dust or other foreign particles to enter the transmission.
Check the connector for rust, dirt, or oil, then connect the connectors.