What is a spool differential and why is it only for off-road use?

A spool differential locks both axle shafts together, forcing both wheels to rotate at the same speed. This provides 100% traction but makes turning more difficult on pavement, leading to tire wear and unpredictable handling. It's ideal for dedicated off-road or drag racing vehicles where maximum traction is the priority.

What gear ratio is required for this Yukon spool?

This Yukon Gear & Axle spool is designed for AMC Model 20 axles with a 3.08 or numerically higher gear ratio. Using it with a lower gear ratio may cause issues with installation and performance.

Does this spool come with any installation hardware?

This product includes the Yukon steel spool itself. It is designed to install in place of your existing differential carrier assembly, and you will typically reuse your original differential bearing and gear set hardware. Refer to the manufacturer's installation instructions for a complete list of required components and procedures.

Yukon Gear Steel Spool For Model 20 w/ 29 Spline Axles / 3.08+

1 / 5

Specifications

Brand: Yukon Gear & Axle
Part #: YP FSM20-3-29
UPC: 883584320494

Yukon Gear Steel Spool For Model 20 w/ 29 Spline Axles / 3.08+

Name: Yukon Gear Steel Spool For Model 20 w/ 29 Spline Axles / 3.08+
Brand: Yukon Gear & Axle
Price: 478.89 USD
Availability: InStock

$478.89

On Backorder

Order now to reserve yours — we'll ship as soon as stock arrives. Full refund if we're unable to fulfill.

Yukon Gear Steel Spool for AMC Model 20 w/ 29 Spline Axles / 3.08+. Converts diff to 100% lockup for dedicated off-road use.

Key Features

Fits AMC Model 20 axles with 29 spline axles and 3.08 and up gear ratios.
Converts the differential to 100% lockup for maximum traction.
Constructed from durable 8620 steel for strength.
Heat-treated for enhanced durability in demanding applications.
Designed for dedicated off-road and drag racing use only.
Installs in place of the original differential carrier assembly.

⚠️ CA WARNING: This product can expose you to chemicals known to the State of California to cause cancer and/or birth defects or other reproductive harm. Learn more

Secure CheckoutFast Shipping631-982-0042

Will this fit your vehicle?

Product Details

If you're looking to get maximum traction for serious off-road adventures or drag racing, a Yukon Gear & Axle steel spool is a solid option. This spool is designed to replace your differential carrier assembly in AMC Model 20 axles with 29 spline axles and a 3.08 or numerically higher gear ratio. It provides a full 100% lockup, meaning both rear wheels will always turn together, ensuring you can power through tough terrain or launch hard off the line.

Yukon makes these spools from strong 8620 steel and then heat treats them for added durability. This construction is built to handle the demands of dedicated performance applications. Because it locks both wheels together constantly, this type of differential isn't recommended for street-driven vehicles, as it can make turning more difficult and cause tire scrub. It's a straightforward conversion for vehicles like the Jeep CJ7, AMC Javelin, or Hummer H1 when you need unwavering traction.