Yukon Gear 1995-2015 Toyota Tacoma Rear Diff w/ Grizzly Locker 30 Spline & 3.90 Ratio Drop Out Assembly

The Yukon YDAT100-390YGL Dropout Assembly is a factory-preset third member unit designed for Toyota 8.4″ rear differential housings using 30-spline axles. Its internal gearing is already shimmed and backlashed to spec, so you can install it into your rear housing, add gear oil, and drive. For enhanced off-road traction, this version includes a mechanical Grizzly Locker.

Product Specifications

• Ratio: 3.90
• Spline Count: 30 spline axles
• Locker: Mechanical Yukon Grizzly Locker
• Case Material: Nodular iron, chosen for strength and resistance to flex
• Dropout Type: Complete third member with yoke pre-installed
• Factory Setup: Fully shimmed, preloaded, and backlashed—no assembly work needed on your end

Fitment & Vehicles

• Fits Toyota 8.4″ rear housings using 30-spline axle assemblies—common in T100, older Tacomas, early Tundras, and similar setups
• Confirm your existing axle and housing specs before ordering to avoid misfit

Why This Dropout Stands Out

• Zero Assembly Required: Eliminates the need to shim or set backlash—just insert and bolt it in place
• Strength You Can Rely On: Nodular iron case resists distortion and maintains consistent gear engagement
• Traction on Demand: Grinder-grade Grizzly Locker ensures torque is delivered to both wheels under load

Install Guidelines & Tips

• Use proper gear oil and perform gear break-in steps.
• Tighten housing bolts to spec and verify seal integrity.
• Expect higher tire wear in tight turns due to full locking during torque events.
• Ensure correct bearing and axle shaft compatibility before installation—misfits can damage internals.

Questions? We’re Here to Help.

Have questions about suspension or drivetrain upgrades for your truck? Our team at FASS Motorsports is here to assist:

• Phone: 636-429-7020
• Email: info@fassmotorsports.com