ZZHZ has very rich experience of producing hoisting machinery. For example, gantry crane , so it can give some advice to us: 
As general, the abrasion of parts will increase with load, when the load which the parts’ bearing is higher than the average design load, the abrasion will increase rapidly.
The test indicates that the abrasion of cylinder will increase 2 times when the engine works in the unstable load. The engine works with normal load, the life will prolong and the incidence of fault will decrease. If the engine works with overload, the life will reduce and the incidence of fault will increase.
Generally, the life of motor of engine is longer than bulldozer and loader’s life. The regular load is decided by operator.
a. the machinery works with overload is prohibited. As a manger who is responsible for construction machinery, the manger should take the construction machinery material and operational manual to the operator. And the operator should master the machinery function and operational rules. The manager shouldn’t withhold the material.
b. the load of machinery should be increased and decreased evenly to make the change of load smoothly. Specifically, the increasing and decreasing of accelerator should keep balance in order to make sure the engine and working device can work smoothly.