Blow the parts with compressed air and gently wipe them. Blow out the bearings with particular care, directing the jet of compressed air in such a way that no rapid rotation of the rings occurs.
Cleaning
Thoroughly clean the gearbox parts before inspection. Use a brush or scraper to remove all deposits and clean the holes and slots from possible contamination; then rinse to remove and dissolve any remaining oil.
Blow the parts with compressed air and gently wipe them. Blow out the bearings with particular care, directing the jet of compressed air in such a way that no rapid rotation of the rings occurs.
Crankcase and covers
There should be no cracks on the crankcase, and no wear or damage on the surface of the bearing bores.
The mating surfaces of the clutch housing, rear cover and bottom cover must not be damaged to prevent misalignment of the axles and insufficient tightness causing oil leakage. Smooth out minor damage with a file. If parts are excessively damaged or worn, replace with new ones.
Check the condition of the front cover and make sure that the input shaft does not touch it when rotating. If shaft and cover misalignment is found, replace damaged parts. Check if the oil drain hole in the input shaft cover is clogged (shown by the arrow in Fig. Interior view of the clutch housing). Clean the drain plug.
Stuffing box
Check the seals for damage, excessive wear, and roughness on the lips of the seals.
Wear of the working edges of the glands in width is allowed no more than 1 mm. If even a slight defect is found, replace the seals with new ones.
Shafts
On the working surfaces and splines of the secondary shaft, damage and excessive wear are not allowed; the flange of the flexible coupling must slide freely without jamming on the splines. The rolling surfaces of the needles at the front end of the shaft must be free of roughness and burrs.
Check the condition of the rolling surfaces of the needles in the input shaft bore.
Check the intermediate shaft, which is not allowed to chip or excessive wear of the teeth.
The surface of the reverse gear shaft must be perfectly smooth, without any signs of binding. The size of the mounting gap between the axle and the bushing of the intermediate reverse gear is 0.056–0.09 mm, the maximum allowable gap is 0.15 mm. Check the clearance by measuring the diameters of the axle and gear bushing. For new parts, the diameters are equal:
- pinion axle - 19.9+0,094–0,079 mm;
- internal diameter of the pressed sleeve - 20+0,07-0,05 mm.
Eliminate minor irregularities on the surfaces with fine emery cloth, in case of large damage and deformations, replace the shaft with a new one.
Gears
The gears must not show any damage or excessive wear on the teeth. Pay special attention to the condition of the ends of the teeth on the synchronizer rims.
The contact patch of the meshing of the teeth in the gear should be located over the entire working surface, which should be smooth and without signs of wear. Check the engagement gap between the gears, the installation value of which should be 0.10 mm; wear limit - a gap of 0.20 mm.
The mounting gap between the bushing and the gear of the 1st gear and between the secondary shaft and the gears of the 2nd and 3rd gears must be 0.05–0.10 mm; wear limit - a gap of 0.15 mm.
If the wear exceeds the allowable limits, replace the gears with new ones.
Bearings
Ball or roller bearings must be in perfect condition. Their radial clearance should not exceed 0.05 mm.
Pressing the inner ring against the outer ring with your fingers, turn one of them in both directions, while rolling should be smooth. The surface of the balls or rollers and the raceways of the rings must not be damaged. Replace damaged bearings with new ones. When replacing the front bearing of the input shaft, use the ejector A.40006 (see subsection 4.3); while the flywheel can not be removed.
Rods and forks
Deformation of the shift forks is not allowed. The rods should slide freely without significant play in the crankcase bores.
Check up a condition of blocking crackers of rods, springs and balls of clamps. Parts that show signs of seizing or wear must be replaced with new ones.
Hubs, couplings and synchronizer rings
Check for signs of seizing on the hubs of the 1st-2nd and 3rd-4th gear clutches, especially on the sliding surfaces of the clutches.
Pay special attention to the condition of the ends of the coupling teeth.
Excessive wear of the surface of the blocking rings is not allowed. They must be replaced if they butt against the synchronizer sleeve. Remove possible irregularities that prevent free sliding with a velvet file. Parts that are worn out more than acceptable limits, replace with new ones.