Remove the front gearbox housing cover, which is integral with the clutch release bearing guide sleeve.
Using pliers, remove the snap ring and adjusting ring from the front end of the input shaft.
Using a puller, first press the rear bearing of the input shaft, then the front bearing of the intermediate shaft.
Unscrew the plug of the gear selector rod retainer.
Remove the reverse light switch.
Loosen the bolts securing the rear cover to the gearbox housing and remove the rear cover.
Knock out the pins from the shift forks (slide them completely along the chamfers of the synchronizer sliding sleeves) (see photo).
Loosen the reverse gear lever mounting bolt and remove the lever.
Remove the plug of the gear selector rod retainer, take out the spring and the retainer bushing. Take out the plugs of the gear shift rods and partially knock out first the III and IV gear shift rod, then the gear selector rod, having first turned the gear selector rod. (When doing this, be careful not to damage the guide ribs of the gear shift forks.)
Remove the rod and fork for shifting III and IV gears.
Knock out the pin from the rod and remove the 1st and 2nd gear shift fork.
Remove the reverse gear engagement rod and the 1st and 2nd gear shift fork rod.
To facilitate possible subsequent disassemblies, it is recommended to shorten the locking pins of the shift forks of I and II, III and IV gears by approximately 1 mm.
Remove the detent balls, locking balls and their springs.
Remove the secondary shaft flange.
Unscrew the four Allen key socket head bolts (5 mm socket wrench) securing the secondary shaft rear bearing cover and remove the cover.
Heat the rear cover of the gearbox housing to a temperature of 80-100°C to press out the rear bearing and remove the gear blocks.
Disassemble the gear units in the following order: primary shaft, synchronizer cone ring and needle bearing, synchronizer clutch hub retaining ring for III and IV gears, adjusting ring, synchronizer clutch hub, III gear and needle bearing.
Press out the secondary shaft, resting the puller against the 2nd gear pinion (see photo).
Disassemble the secondary shaft.