Check for excessive wear on the synchronizer locking rings: if the axial clearance between the end face of the locking ring and the end face of the synchronizer ring gear is less than 0.8 mm, the rings must be replaced (for new blocking rings this gap is 1.0 mm).
Partially assemble the secondary shaft in the reverse order of disassembly, first pressing the 2nd gear onto the shaft, and lastly the reverse gear.
Install the adjusting ring on the secondary shaft and press the speedometer drive pinion onto it until it stops. Measure the secondary shaft axial clearance, which should be within 0-0.09 mm. If it deviates from the norm, achieve the proper size by selecting the thickness of the adjusting ring.
Turn the secondary shaft over and press the parts onto it in the reverse order of disassembly, while it is necessary to select an adjusting ring installed on the bearing of such a thickness as to ensure a tight fit of the parts.