Abrasive have on is another issue, usually caused by particulate issue suspended in the oil. That is why Used Oil Investigation for wear metals and contaminants is critical to monitor gearbox wellness. Should not be used in cars which has a wet clutch/friction drives: the lubricating Qualities of STP® Oil https://alexispydhk.activosblog.com/33116668/gearbox-oil-treatment-for-dummies