Misalignment No Beauty in Gearsets

When we have problems with gearset failure, a common diagnosis is misalignment. What exactly is that and how do we prevent it? The second most common "killer" of good gear sets is misalignment (dirt, or abrasive wear, is first). Gear teeth simply won't carry the load if they don't touch, and the portion that does touch has to carry an overload to make up for the missing contact area.