What is the shiny iron foam on the gearbox magnet screw?

1, insufficient gearbox oil, which will lead to increased friction between bearings and parts and iron foam, so it is necessary to add gearbox oil in time.

2, gear wear, after a long period of use of the gearbox, gear wear, will produce fine iron filings, gearbox oil should be replaced, so as not to affect the normal use of the gearbox.

3. The gear shift is not good. When the driver shifts gears, he doesn't step on the clutch pedal to the end, resulting in shifting gears and iron filings.