USA Standard Steel Spool For Model 20 w/ 29 Spline Axles / 3.08+

Built from tough 8620 steel and heat-treated for extra strength, this USA Standard Gear spool is designed for serious traction. It replaces your differential carrier assembly to give you 100% lockup, meaning both rear wheels are always driven together. This is a fantastic upgrade for vehicles that see dedicated off-road use or are used for drag racing, where maximum grip is essential. It's specifically made for Model 20 axles with 29 spline axles and works with 3.08 and numerically higher gear ratios.

Because it locks both wheels together, this spool is not recommended for street-driven vehicles. On pavement, it can cause tire scrub, increased wear, and make turning more difficult. However, for applications where you need unwavering power to both rear wheels, like crawling over rocks or launching off the line, a spool is a cost-effective way to achieve that goal. It fits a wide range of vehicles, including many Jeep CJ models, American Motors cars from the 70s, and even some Hummer H1 models.