A motor vehicle differential bearing pre-load mechanism which provides for the simultaneous use of a collapsible spacer which plastically deforms and has a close to linear load to deflection band on one side of a motor vehicle differential assembly and a threaded adjuster on the other side of the motor vehicle differential assembly to axially pre-load the differential bearings in motor vehicle differential axles or on any shaft with bearings which requires an axial pre-load. Typically, the axial pre-load of the differential bearings decreases as wear of the differential bearings occurs when mechanical shims or a threaded adjuster without a collapsible spacer have been used. In practice, once the motor vehicle differential case with the differential bearings is installed in the motor vehicle differential carrier with a new non-compressed collapsible spacer, the threaded adjuster is tightened until the collapsible spacer plastically deforms and until the ring gear and the pinion gear are adjusted to provide an appropriate gap between the pinion teeth and the ring gear teeth to provide proper backlash.