Description

Taper Roller Bearing – outer pinion bearing in the differential final drive assembly.

The drive pinion is carried on a pair of opposed taper roller bearings inside the differential housing. This is the outer bearing of that pair, sitting between the pinion flange and the pinion head, and it carries the axial thrust generated as the pinion drives the crown wheel. Bearing preload is set by the collapsible spacer or shim stack behind the flange nut, so the pinion oil seal, spacer and flange nut are normally renewed at the same time.

Worn pinion bearings show as a rumble that changes between drive and overrun, or as detectable end float at the pinion flange. Both pinion bearings should be replaced together, with pinion preload and crown wheel backlash reset on assembly.