Changchun BMW 1 series always rattles in the back.

1, too low transmission oil will cause unsmooth gear shifting, resulting in abnormal engine sound.

2. The oil leakage in the oil system of the gearbox will also affect the gear shifting of the gearbox, which will lead to abnormal engine noise.

3. The old gearbox filter will cause oil blockage, so replace it with a new filter.