Superfinished Differential Gears: Is It Worth It?
Superfinishing polishes the gear tooth surface to a mirror finish. It sounds like a gimmick, but there are real benefits for some diffs.
Superfinishing is a chemical and mechanical process that removes the microscopic peaks left by machining and grinding on a gear tooth. The result is a smoother, harder wearing surface that runs cooler and quieter.
Where it pays off
For race diffs and high load tow vehicles, superfinished gears shed heat better and are less likely to pit under sustained load. They also break in faster, which matters when a new gearset is going straight into service.
Where it does not
For a standard road car with a quality gearset and the right oil, the gains are small. We will tell you honestly if it is worth it for your build, and we will not recommend it where it does not make sense.
