What is a spool and why would I use one?

A spool is a differential replacement that locks both axle shafts together, ensuring they always rotate at the same speed. This provides 100% traction, which is ideal for dedicated off-road vehicles or drag racing where maximum grip is essential.

Is this spool suitable for my daily driver?

No, this spool is specifically not recommended for street-driven vehicles. The constant lockup can cause tire scrub, increased wear, and make steering difficult during low-speed turns on pavement.

What gear ratio is this spool designed for?

This Yukon Gear & Axle spool is designed for Dana 44 differentials with a gear ratio of 3.73 or numerically lower (e.g., 3.55, 3.08, 2.73).

Yukon Gear & Axle Dana 44 Spool ZP FSD-3-30DN

Name: USA Standard Steel Spool For Dana 44 w/ 30 Spline Axles / 3.73 & Down
Brand: Yukon Gear & Axle
Price: 317.89 USD
Availability: InStock

USA Standard Steel Spool For Dana 44 w/ 30 Spline Axles / 3.73 & Down

$317.89

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 & Axle steel spool for Dana 44 with 30 spline axles and 3.73 ratio & down. Provides 100% lockup for dedicated off-road use.

Key Features

Fits Dana 44 differentials with 30 spline axles and 3.73 gear ratio or numerically lower.
Provides 100% axle lockup for maximum traction in off-road and drag racing applications.
Constructed from durable 8620 steel for strength.
Heat-treated for added durability under stress.
Installs in place of the differential carrier assembly.
Not recommended for street-driven vehicles.

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Will this fit your vehicle?

Product Details

If you're building a dedicated off-road rig or a drag racing machine and need maximum traction, a spool is a cost-effective way to get 100% lockup. This USA Standard Gear spool is built for Dana 44 differentials that use 30 spline axles and a gear ratio of 3.73 or numerically lower. It replaces your factory differential carrier assembly, giving you a solid, locked axle that ensures both rear wheels turn at the same speed, all the time. This is a serious upgrade for vehicles that spend their time on the trail or at the strip, not on public roads.

Constructed from tough 8620 steel, this spool is heat-treated to handle the extra stress that comes with a locked differential. The installation is straightforward since it's designed to fit directly in place of your existing differential carrier. While it offers incredible traction for off-road adventures or racing, it's important to remember that this type of setup is not recommended for street-driven vehicles due to the way it affects steering and tire wear during low-speed turns.