Disassembling the G55 and G56 gearbox [Toyota Dyna Y50]

1. Remove the release fork and bearing.

2. Remove the reversing light switch and the speedometer driven gear.

3. Remove the clutch housing from the gearbox housing.



4. Remove the gear shift lever housing assembly.





5. Remove the crankcase extension.





6. Remove the front bearing housing and use round-nose pliers to remove the retaining rings.



7. Disconnect the intermediate plate from the gearbox housing.

a) Using a plastic hammer, carefully tap the gearbox housing.

c) Separate the gearbox housing from the intermediate plate.



8. Clamp the intermediate plate in a vice using the two clutch housing mounting bolts, flat washers and suitable nuts.

Warning: Install flat washers upside down compared to their normal position. Increase or decrease the number of flat washers to achieve a position where the end of the bolt tip and the end surface of the nut are flush with each other.

9. Unscrew the threaded plugs, remove the springs and retainer balls.

a) Using the tool, unscrew the threaded plugs.



b) Using a magnetic finger, remove the springs and balls of the retainers.



10. Remove the split pin and bolt.



a) Using a punch with a thin cylindrical end and a hammer, knock out four pins.

b) Remove the bolt from gear shift fork No.1.



11. Using round-nose pliers, remove the four shift fork rod retaining rings.



12. Remove shift fork rod No.4 and shift fork No.3.

a) Pull the shift fork rod #4 away from the intermediate plate.

Warning: Catch the retainer balls and pin with your hand, if they do not fall out, use the magnetic finger to remove them.

b) Remove the shift fork rod No.4 and shift fork No.3.



13. Remove the ball and head of the reverse gear engagement rod.



14. Remove the shift fork rod No.3.

a) Pull the shift fork rod #3 away from the intermediate plate.

Warning: Catch the pins with your hand, if they do not fall out, use the magnetic finger to remove them.

b) Remove the shift fork rod No.3.



15. Remove the shift fork rod No.2 and shift fork No.2.

a) Pull the shift fork rod #2 away from the intermediate plate.

Warning: Catch the pin with your hand, if it does not fall out, use the magnetic pin to remove it.

b) Remove shift fork No.2 and rod.



16. Remove the shift fork rod No.1 and the first and second gear shift head.





17. Remove the reverse gear idler gear and idler gear shaft.

a) Remove the intermediate gear axle lock.

b) Remove the intermediate gear and its axle.



18. Remove the reverse gear selector lever from the bracket.



19. Measure the axial clearance of the fifth gear intermediate gear.

Using a set of feeler gauges, measure the axial clearance of the fifth gear intermediate gear.

• Nominal clearance - 0.1 -0.3 mm
• Maximum gap - 0.3 mm

20. Remove the fifth gear synchronizer hub, synchronizer ring, needle bearings and fifth gear intermediate gear with hub coupling No.3.

a) Engage the gears.

b) Using a hammer and chisel, chisel the nut.



c) Remove the lock nut.

d) Disengage the gears.



d) Using a puller, remove the fifth gear synchronizer hub, synchronizer ring, needle bearing and fifth gear intermediate gear.





21. Remove the spacer sleeve and ball using the magnetic pin.



22. Unscrew the two bolts and remove the reverse gear shift linkage bracket.



23. Using a special tool, unscrew the four bolts and remove the rear bearing housing.



24. Using round-nose pliers, remove the retaining ring.



25. Remove the secondary shaft, intermediate shaft and primary shaft as one assembly from the intermediate plate.

a) Remove the secondary shaft, intermediate shaft and primary shaft from the intermediate plate as follows: pulling the intermediate shaft towards you and hitting the intermediate plate with a plastic hammer as shown in the figure.

b) Remove the primary shaft with the 13-roller needle roller bearing from the secondary shaft.



26. Using a punch and hammer, knock the intermediate shaft bearing out of the plate.



27. Remove the speedometer drive gear.

a) Using round-nose pliers, remove the retaining ring.

b) Remove the speedometer drive gear.

c) Using a magnetic finger, remove the steel ball.

d) Using round-nose pliers, remove the retaining ring.



28. Measure the axial clearance of each gear.

• Nominal clearance - 0.10 - 0.25 mm
• Maximum gap - 0.25 mm

29. Remove the fifth gear pinion, bearing, first gear pinion, bearing inner race and needle roller bearing.

a) Using two screwdrivers and a hammer, remove the retaining ring.



b) Using a press, remove the fifth gear pinion, bearing, first gear pinion and bearing inner race.

d) Remove the needle roller bearing.

30. Remove the synchronizer ring.



31. Using the magnetic finger, remove the retainer ball.



32. Remove the hub coupling No.1 together with the second gear pinion.

a) Using a press, remove the hub coupling No.1, the synchronizer ring and the second gear.

b) Remove the needle bearing.



33. Remove the hub coupling No.2 with the third gear assembly.

a) Using round-nose pliers, remove the retaining ring.



b) Using a press, remove the hub coupling No.2, the synchronizer ring and the third gear.

c) Remove the needle bearing.



34. Remove the outer gear selector lever and shaft.

a) Remove the locking pin and nut.

b) Remove the outer gear selector lever and shaft from the shift mechanism housing.



35. Remove the gear shift lever and cover.



36. Remove the gear selection and engagement lever and shaft.

a) Using a hammer and punch, knock out the pin.



b) Remove the gear selection and engagement lever and shaft.



37. Remove the seat and spring.



38. Remove the reverse gear locking pin and spring.

a) Screw the special tool into the pin and pull it out.



b) Remove the reverse gear locking pin and spring.