Clutch housing, transmission housing, cover
There should be no cracks, chips on the gearbox and clutch housings, and wear or damage on the surface of the bores for bearings. The mating surfaces of the clutch and gearbox housings must be free of dents, scratches and other damage that could lead to loss of tightness of the assembly.
Check the condition of the breather to make sure it is clean and in good working order. Check the condition of the rear cover and make sure that the oil level indicator is intact, that the surface of the cover in contact with the gearbox housing is not damaged. Clean the magnet from wear particles. Minor damage to surfaces is eliminated with sandpaper.
During assembly, the damaged areas are lubricated with a sealant used for the engine (see sect. «Cylinder head assembly»). If the parts are severely damaged or worn, replace them with new ones.
Seals, gaskets
Check the condition of the working edges. On the edges, unevenness and high wear are not allowed. Formation as a result of wear on the working edge of the cylindrical belt of more than 1 mm is not allowed. There should be no nicks or dents on the seating surface of the stuffing box frame. Even with minor damage, the seal is replaced with a new one. Sealing gaskets are recommended to be replaced with new ones.
Shafts
Check the condition of the teeth of the gears of the primary and secondary shafts. Teeth should not have chips, nicks and wear. On the landing belts of the shafts on which the bearings are located, there should be no scuffing and wear.
The slots should not have dents and nicks that make it difficult to assemble parts. If necessary, eliminate defects with an emery cloth or a velvet file. If shaft defects cannot be repaired; replace the shaft with a new one.
Gears
At the ends of the teeth of the synchronizer crown, there should be no significant crushing or chipping. The contact patch between the teeth of the gears in engagement should extend to the entire working surface of the teeth; the specified tooth surface must not show any wear.
Bearings
Ball, roller and needle bearings must be in perfect condition. The radial clearance of ball and roller bearings must not exceed 0.05 mm. On the surfaces of balls, needles and rollers, as well as on the running tracks of rings, bushings and gears, damage is not allowed. Damaged bearings, bushings and gears are replaced with new ones. The needles and cages of the needle bearings must not be damaged or worn.
Rods, forks
Deformation of the forks, rods and levers for selecting and shifting gears is not allowed. The rods must slide freely in the crankcase bores and bushings. Check the condition of the springs and retainer balls. Parts that show signs of wear or seizing are replaced with new ones.
Hubs, couplings, synchronizer rings
Check that the hubs are not damaged, especially on the sliding surfaces of the couplings. Particular attention is paid to the condition of the ends of the coupling teeth. There should not be excessive wear of the blocking rings: if the axial clearance between the end of the blocking ring and the end of the gear rim of the gear synchronizer is 0.6 mm or less, the rings are replaced with new ones. Damage or seizing marks on balls, springs and crackers are not allowed. Possible irregularities that prevent slipping of couplings and blocking tracks are eliminated with a velvet file. Damaged and worn parts are replaced with new ones.
Differential
Check the condition of the surface of the axis of the satellites, side gears, washers, satellites and the surface of the differential box. Check the condition of the landing belts on the differential box.
In case of minor damage to the surfaces, irregularities are eliminated with a fine-grained sandpaper, and in case of significant damage, the parts are replaced with new ones.
Select mechanism and gear change actuator
Check the condition of the gear selector lever, its springs and the lever axis. Worn and damaged parts are replaced. Check the condition of the gear selection rod, the fastening and the condition of the gear selection lever, the condition of the oil seal and the protective cover. Worn and damaged parts are replaced. Check the fit of the gear lever in the ball joint. The lever must rotate freely in the support, without jamming and not have free play. There should be no noticeable play in the hinge connecting the gear lever to the drive rod. Deformation of the drive rod and jet thrust and damage to the protective cover are not allowed.
Deformed rods are replaced or straightened.
The dimensions of the main mating parts and the limits of permissible wear in operation are given in Table. 10.