Mainshaft Disassembly, Inspection, and Reassembly

Disassembly 

1. Remove the thrust needle bearing (A), the mainshaft 5th gear (B), the needle bearing (C), the thrust needle bearing (D), the mainshaft 5th gear collar (E), the 4th/5th clutch (F), and the O-rings (G) from the mainshaft (H).
   Fig 1: Identifying Thrust Needle Bearing, Mainshaft 5th Gear, Needle Bearing, Thrust Needle Bearing, Mainshaft 5th Gear Collar And O-Rings

   Courtesy of AMERICAN HONDA MOTOR CO., INC.
2. Remove the set ring (I), the needle bearing (J), and the sealing rings (K).

   Inspection 

3. Inspect the thrust needle bearing and the needle bearing for wear and rough movement.
4. Inspect the splines for excessive wear and damage.
5. Inspect the mainshaft 4th gear (L) for wear and damage, and inspect the mainshaft 4th gear bearing for wear and rough rotation.
6. Replace the mainshaft 4th gear if the gear or the bearing is worn or damaged (see MAINSHAFT 4TH GEAR REPLACEMENT  ).
7. Check the shaft bearing surfaces for scoring and excessive wear.

   Reassembly 

8. Lubricate all parts with ATF during reassembly.
9. Install new sealing rings, the needle bearing, and the set ring.
10. Wrap the shaft splines with tape to prevent O-ring damage, install new O-rings on the mainshaft, then remove the tape.
11. Install the 4th/5th clutch.
12. Install the mainshaft 5th gear collar, the thrust needle bearing, the needle bearing, the mainshaft 5th gear, and the thrust needle bearing.