YIKONG YK4106 RC car gear box is too noisy how can I reduce the noise?

Check whether the lubricating oil in the gear box of YIKONG YK4106 RC car is sufficient or deteriorated, if it is insufficient, add it, if it is deteriorated, replace it with suitable lubricating oil to ensure that the gears are well lubricated. Check whether the gears are worn and have burrs, the worn gears need to be replaced, and the burrs can be sanded. Tighten the fixing screws of the gear box to prevent noise from loosening. In addition, check whether there are foreign objects in the gear box, clean up foreign objects.