Special Tools Required

Install the 49 x 66 x 3 mm thrust needle bearing (A), the 45 x 50 x 25 mm needle bearing (B), 4th gear (C), and the 49 x 66 x 3 mm thrust needle bearing (D), then install the selected 4th gear washer (E) in the direction shown by aligning the tab (F) of it with the groove (G) of the third shaft (H).

Fig 1: Identifying Third Shaft Assembly
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Install the 36 mm cotters (I), the cotter retainer (J), the snap ring (K), the 37 x 42 x 25 mm needle bearings (L), and 6th gear (M) on the third shaft.
Apply ATF to the reverse selector hub splines (A), and slide the reverse selector hub (B) in the direction shown over the third shaft (C), then press it into place using the 40 mm I.D. driver handle, the 30 mm I.D. bearing driver attachment, and a press.

Fig 2: Locating Reverse Selector Hub Splines, Reverse Selector Hub And Third Shaft
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Install the reverse gear collar (A), the 35 x 41 x 32 mm needle bearing (B), the reverse selector (C), and the reverse gear (D) on the third shaft (E).

Fig 3: Locating Reverse Gear Collar, 35 x 41 x 32 mm Needle Bearing, Reverse Selector, Reverse Gear And Third Shaft
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Wrap the shaft splines with electrical tape, and install new O-rings (F) in the 4th clutch O-ring grooves, then remove the tape.
Install the 4th clutch (G) on the secondary shaft, and secure the 4th clutch with the 35 mm snap ring (H).
Install new sealing rings (I).