Spicer 2-2-1379 1310 Series 4-Bolt Flange Yoke (4.250" Large Ford Bolt Circle, 2.000" Female Pilot)

Eliminate high-speed driveline vibrations, complete your rear-end axle swap correctly, and restore maximum rotational power to your tires with this genuine Spicer 1310 Series 4-Bolt Flange Yoke. Engineered as a high-durability original equipment manufacturer (OEM) component by Dana, this premium adapter flange (Part Number: 2-2-1379) provides the exact structural fitment required to mate a traditional u-joint driveshaft to a factory Ford companion pinion flange.

On rear-wheel-drive cars, muscle cars, and light-duty trucks, the rear axle's pinion companion flange acts as the primary rotational input into the differential gears. When building a custom driveshaft, converting an old vehicle to a modern Ford 8.8-inch rear end, or refreshing a worn factory driveline, finding an exact match for the companion flange is critical. Over decades of service or high-torque acceleration on the drag strip, a vehicle's original flange yoke can suffer structural fatigue, warped ears, or deep rusting in the snap ring grooves. A compromised or poorly balanced yoke allows the universal joint caps to shift out of alignment, introducing loose backlash into your drivetrain. This mechanical play results in a harsh clunking sound when shifting gears and an aggressive, low-frequency chassis vibration at highway speeds. Replacing it with this authentic, pre-balanced Spicer steel forging resolves this play and prevents catastrophic on-road component failure.

Precision-cast from premium micro-alloy structural steel and balanced to exact factory blueprint tolerances, the 2-2-1379 features a 4.250-inch diagonal bolt circle configuration with four drilled 0.484-inch holes tailored for the large factory Ford mounting pattern. It relies on a precision-machined 2.000-inch female pilot register to guide the yoke tightly over the pinion flange stub, guaranteeing flawless concentric alignment and completely mitigating rotational runout. Dimensioned explicitly for the globally trusted 1310 Series driveline architecture, it utilizes an outside snap ring (OSR) layout designed to securely cradle standard 1.062-inch diameter universal joint bearing caps with a 3.219-inch width.

Component Highlights:

• Large Ford 8.8" Integration Essential: Engineered specifically to bolt directly onto the large-pattern factory pinion flanges found on full-size Ford vehicles, Mustang Cobras, and 8.8-inch axle swaps.

• Flawless Rotational Alignment: Outfitted with a precision-bored 2.000-inch female center pilot to lock flawlessly onto companion flanges, eliminating undercarriage harmonics and protecting your internal pinion bearings.

• Genuine Spicer Forged Steel: Cast from high-tensile steel alloy and heat-treated to maximize grain density, ensuring the yoke ears resist spreading under heavy torque spikes or sudden acceleration.

• Pre-Balanced Performance: Machined to strict factory weight distribution metrics to guarantee smooth, vibration-free performance that reduces driver cockpit fatigue.

Drivetrain & Dimensional Specifications:

• Driveline Series Architecture: 1310 Series (3.219" cap-to-cap snap ring span | 1.062" bearing cap diameter).

• Flange Configuration Style: Rectangular/Square 4-Bolt Flange.

• Bolt Circle Diameter (BCD): 4.250 inches (Measured diagonally).

• Hole Spacing (Center-to-Center): 3.005 inches (Horizontal & Vertical).

• Bolt Hole Diameter: 0.484 inches (Drilled for 12 mm or 7/16" 12-point bolts).

• Pilot Register Diameter & Type: 2.000 inches (Female Pilot / F).

• Centerline of Joint to Flange Face: 1.625 inches.

• Flange Swing Diameter: 5.219 inches.

• Compatible U-Joint Kits: Spicer 5-153X (Greaseable), 5-1310X (Non-Greaseable), or 5-3613X (Coated for Aluminum Shafts).

Primary Vehicle & Custom Applications:

• Ford 8.8-Inch Rear End Swaps: The industry-standard adapter yoke for installing a 1310-series custom or Jeep driveshaft into a Ford 8.8-inch rear end setup (commonly sourced from 1995–2004 Ford Explorer, Mustang, Ranger, and full-size truck platforms).

• Ford Vehicles: Fits various classic and modern rear-wheel-drive Ford light trucks, SUVs, and muscle cars utilizing the large-pattern 4-bolt companion flange.