Check if there is any damage to the main gear teeth and if the contact spots on the working surfaces of the teeth are correctly located. If the wear is unacceptable, replace the parts with new ones; if the engagement is incorrect, find the cause.
Note: The drive and driven gears are supplied as a set in spare parts, selected according to noise and contact, therefore if one gear is damaged, both are replaced.
Check the condition of the satellite holes and the surfaces of their axis; if there is any damage, replace the parts with new ones.
Check the surfaces of the axle shaft gear journals and their mounting holes in the differential box, the condition of the holes in the box for the satellite axle. If necessary, replace worn or damaged parts.
Inspect the surfaces of the axle gear bearing washers, replace damaged washers. When replacing washers, select new ones according to thickness.
Inspect the roller bearings of the pinion gear and differential case; they must be free of wear, with smooth working surfaces. Replace the bearings at the slightest doubt about their performance, poor condition of the bearings can be the cause of noise and seizing of the teeth.
Check the crankcase and differential box for deformations or cracks; replace them with new ones if necessary.