Wheel loaders often face gearbox abnormal noise and vibration problems during long-term heavy-load operation, which not only affect driving comfort but also may lead to serious failures such as gear wear and bearing damage if not handled in time. This case summarizes a typical fault diagnosis and maintenance process based on actual engineering equipment maintenance.
A 5-ton wheel loader working in a sand and gravel yard began to show obvious abnormal noise when shifting gears, accompanied by slight vibration of the whole machine, especially during acceleration and load lifting. The noise was more obvious in the middle and high speed ranges, and the fault became more serious after continuous operation. After preliminary inspection, the maintenance personnel excluded engine abnormalities and focused on the gearbox and transmission system.
First, the gearbox oil level and oil quality were checked. It was found that the transmission oil was dirty, contained a small amount of metal debris, and had a burnt smell, indicating internal wear and overheating. Then, the gearbox was disassembled for inspection. The main fault points included severely worn bearing rollers, damaged gear meshing surfaces, and loose connecting bolts of the transmission shaft. These problems caused unstable power transmission, resulting in noise and vibration.
The maintenance process included completely replacing the deteriorated transmission oil and oil filter, replacing worn bearings and damaged gears, re-tightening all connecting fasteners to specified torque, and adjusting the clearance between gears and shafts. After reassembly, the gearbox was tested for idling and load operation. The abnormal noise disappeared completely, and the vibration returned to normal.
To prevent similar failures, daily maintenance should include regular inspection of transmission oil quality and level, avoiding long-term overload operation, reducing rapid shifting and sudden acceleration, and replacing transmission oil and filters strictly according to operating hours. Timely handling of minor abnormalities can effectively avoid major gearbox damage and reduce maintenance costs.
