CT-1 Spool Shim Kit Large O.D.

The CT-1 Spool Shim Kit Large O.D. is a precision differential shim assembly engineered for serious off-road and high-performance vehicle builders. This kit addresses the critical need to eliminate backlash and side-to-side play in spool-style differential carriers, a common challenge when upgrading to aggressive gear ratios or installing lockers. Whether you're prepping for trail duty, drag racing, or maximizing traction in a street machine, proper shim selection and installation directly impacts differential noise, durability, and reliable power delivery.

Manufactured by Diversified Machine from hardened steel, the CT-1 Spool Shim Kit Large O.D. features a 2.230-inch inner diameter bore to match standard spool carrier applications. The large outer diameter design accommodates wider, higher-load differential housings, distributing clamping forces evenly across the carrier face. Steel composition ensures consistent stiffness and resistance to deformation under the extreme thrust loads generated during aggressive acceleration or torque-biasing operation. This kit provides the precision thickness and dimensional stability required to maintain proper ring-gear-to-pinion depth and preload geometry.

Installers and differential builders rely on shim kits like this to dial in carrier setup during rebuild or retrofit operations on full-floating axles and independent rear suspensions. The compact kit format—measuring 3.1 by 4.05 inches and weighing just 0.07 pounds—ships as a complete solution, eliminating guesswork during assembly. Compatibility spans most heavy-duty spool applications in 9-inch Ford, 12-bolt Chevy, and Dana differentials where a 2.230-inch spool bore is present. Proper shimming is non-negotiable for long-term reliability; this kit delivers the hardened steel shims needed to achieve factory-spec preload and minimize premature bearing wear or gear-mesh noise.