4.88 12 Bolt GM Pass

The 4.88 12 Bolt GM Pass by Richmond is a precision ring and pinion gear set designed for serious off-road and performance driving applications where maximum torque multiplication and traction are critical. This component is specifically engineered for mechanics and enthusiasts upgrading the differential assembly in GM 12-bolt passenger rear axles, particularly in vehicles tackling steep terrain, heavy hauling, or drag racing scenarios where stock ratios limit acceleration and crawling capability.

The 4.88 ratio represents one of the most aggressive options available for this platform, making it the go-to choice for rock crawlers and off-road competitors. Richmond's 4.88 ring and pinion set is manufactured to OEM tolerance specifications, ensuring smooth meshing, minimal backlash variation, and long service life even under extreme load cycling. The gear teeth are precisely cut using advanced CNC processes and heat-treated to withstand the shock loads inherent in low-speed, high-torque off-road maneuvers and repeated acceleration events.

At 4.88:1, the pinion makes 4.88 complete rotations for every single rotation of the ring gear, dramatically increasing torque at the wheels while reducing engine RPM at highway speeds—a tradeoff that prioritizes crawling power and launch traction over top-end cruising efficiency. The compact package dimensions (11.1 x 5.4 x 15.2 inches) and 15.24-pound weight are consistent with complete gear sets ready for differential housing installation. This product is ideal for those looking to enhance their vehicle's performance in demanding off-road conditions.