Cleaning
Before inspection, the parts of the gearbox are cleaned. All deposits are removed with a brush or scraper and the holes and slots are cleaned of possible contamination, then they are washed and blown with a jet of compressed air. It is especially necessary to blow out the bearings well, directing a jet of compressed air so that there is no rapid rotation of the rings.
Clutch housing, transmission housing, cover
The gearbox and clutch housings must be free of cracks, chips, and the surface of the bearing holes for wear or damage. There should be no damage on the mating planes of the clutch housing and gearbox in order to prevent misalignment of the shafts and loss of sealing of the gaskets.
Check the condition of the rear cover to ensure that the breather is in good condition, not dirty, and 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. Damaged or worn parts are replaced with new ones.
Seals, gaskets
Check the condition of the working edges of the seals. 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. 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. Shafts for bearings must be free of burrs and wear. The splines and grooves of the shafts must be free of dents, scuffs and wear to ensure a backlash-free fit of the synchronizer hubs. In the presence of the indicated damage, replace the shaft with a new one.
Gears
On the gears, chipping, wear or nicks on the end side of the synchronizer crown are not allowed. 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. Check the gap in the engagement of the gear teeth with an indicator, having previously installed the gearbox shafts in a special crankcase with windows for access to the gears. The mounting clearance must be 0.10 mm, the limit clearance is 0.20 mm.
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 treadmills of the rings, damage is not allowed. Damaged bearings 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 seizing or wear 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. Excessive wear of the blocking rings, damage or seizing marks on balls, springs and crackers is not allowed. Possible irregularities that prevent the free sliding of couplings and blocking rings 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, semi-axial gears, satellites and the spherical surface of the differential box mating with them. Check the condition of the landing belts for bearings on the differential box.
In case of minor damage to the surfaces, irregularities are eliminated with fine-grained sandpaper, and in case of significant damage, the parts are replaced with new ones.
Gear selection and shifting mechanisms
Check the condition of the forward and reverse gear selection lever, thrust sleeve and washer, gear selection lever axles and locking brackets. 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 should rotate freely in the support, without jamming and should not have free play. Deformation of the drive rod and damage to the protective cover are not allowed. Deformed traction is replaced or straightened.
The dimensions of the main mating parts and the limits of permissible wear in operation are given in Table. 8.