2pc. Pre-Load Assembly - GM 12-Bolt Car

The 2pc. Pre-Load Assembly for the GM 12-Bolt Car is a precision differential bearing preload component designed for serious rear-end builders and performance enthusiasts. This assembly works in tandem with your 12-bolt carrier to establish proper bearing preload, which is essential for eliminating unwanted side-to-side movement in the differential housing. Proper preload is crucial for maintaining bearing longevity and driveline efficiency, making this a vital upgrade for any custom or restoration build.

The two-piece design allows for precise adjustment of bearing preload without over-constraining the system, which can generate excess heat and friction losses. The assembly seats cleanly against the differential carrier, distributing load evenly across the bearing races. By adhering to the manufacturer's recommended preload specifications, you ensure smooth and quiet differential operation.

This preload assembly is essential for anyone rebuilding or upgrading a GM 12-bolt rear axle for street, strip, or off-road use. Whether you're installing a locker, spool, or performance clutch-type differential, proper preload adjustment is the foundation of a solid setup. Its compact form factor and lightweight design make it an ideal choice for performance applications.