Okay so I jacked my car this week-end and notice some surface rust, especially the diff as the main part of it is in iron or steel.
Now this thought came to mind… when rust starts it usually spreads onto the piece and will rot through right, for example a door panel, it will rot through and make some holes possibly.
Now why is it surface rust doesn’t go through the whole diff if it’s all made of iron? If we go by the logic of rust spreads and gets worse, technically the diff should rust completely inside out after some point?
Is it because the metal is very thick or?