Most early failures of heavy truck gears are caused by harsh working conditions and improper maintenance rather than material defects. Overload starting and aggressive slope driving produce excessive instantaneous load, causing hidden micro-cracks on tooth roots.

Long-term high-temperature operation accelerates gear oil oxidation, leading to poor lubrication, dry friction and tooth surface peeling. Bumpy roads cause axial clearance deviation, resulting in unilateral eccentric wear and meshing dislocation.

Standardized loading norms, gentle driving habits and regular lubricant replacement can effectively avoid gear failure and maintain stable transmission performance of heavy trucks.