Answer: The correct way to achieve proper drive pinion gear bearing preload is to torque the pinion nut to the manufacturer’s specifications and then check for preload.
Explanation: Typical starting points for torque specifications are 55 lb-ft for 3/8-inch bolts/nuts, 75 lb-in for 7/16-inch bolt/nuts, and 125 lb-in for 1/2-inch nuts/bolts. Once the nut is properly torqued, check for preload by tapping the end of the pinion gear with a punch to ensure the races are fully seated, shake it to evaluate for excessive play.
Pinion bearings are bearings that support the weight of the drive shaft and transfer power from the differential to the wheels. Preload is the tension that is put on a bearing. In the case of pinion bearings, preload takes place in the form of a collapsible spacer that stays between the bearings. The required amount of tension is obtained by adjusting the space manually.
Other ways to achieve proper drive pinion gear bearing preload include using a crush sleeve or shims. Crush sleeves are used in place of spacers and are designed to be crushed when the pinion nut is tightened. This crushes the sleeve and creates tension on the bearings. Shims can also be used to adjust the space between bearings.
Common problems with drive pinion gear bearing preload include over-tightening or under-tightening of the pinion nut, which can lead to damage or failure of the bearings. It is important to follow manufacturer specifications when torquing the pinion nut and checking for preload.
Hope this helps, and have a great day!