Contaminants can enter your gearbox oil by means of vents or the fill tube in the course of checking/filling. Most of the time, however, contaminants are the result of standard wear. The gearbox filter shields against these contaminants which helps boost gearbox lifestyle. These often have on out with time. https://filtergearbox53172.activoblog.com/37113276/new-step-by-step-map-for-filter-gearbox