The pattern of gear teeth determines how quietly two
meshed gears run. The pattern also describes where on
the faces of the teeth the two gears mesh. The pattern
should be checked during tear down for gear noise diagnosis,
after adjusting backlash and side-bearing preload,
or after replacing the drive pinion and setting up the pinion
bearing preload. The terms commonly used to describe
the possible patterns on a ring gear and the
necessary corrections are shown in Figure 38-39.