Execution order
1. Remove the locking rings from the synchronizer.
2. Mark the position of the coupling relative to the hub.
3. Remove the springs and take the crackers out of the hub grooves.
4. Remove the coupling from the hub.
5. Check the clearance between the gears and the corresponding locking rings (a), which for the synchronizer rings of the 1st and 2nd gears should be 1.10–1.70 mm, and for the synchronizer rings of the 3rd and 4th gears 1.35–1.90 mm (minimum allowable gap 0.5 mm). Otherwise, the locking ring must be replaced.
6. Place the coupling on the hub in accordance with the previously made marks.
7. Insert crackers into the hub grooves.
8. Install springs on both sides of the hub. The bent end of one of the springs should be inserted into one of the crackers, and the bent end of the second spring should be installed into any other cracker. The direction of the second spring coil should be opposite to the first.
9. Install the blocking rings so that the crackers fit into the grooves in the rings.