Yukon YDGGM12T-4-30-1 Dura Grip Posi LSD for GM 8.875 12-Bolt Truck 30-Spline

Regular price: $409.95
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Product Specification:

SKU:YUKYDGGM12T-4-30-1

MPN: YDGGM12T-4-30-1

UPC: 883584260356

Weight: 22.6 lb

Inventory: 4

Type: Differentials

Vehicle Fitment

1963-1987 Chevrolet C10 (2WD/4WD, All Engines)
1963-1987 Chevrolet K10 / K1500 (4WD, All Engines)
1963-1987 Chevrolet Suburban (2WD/4WD, All Engines)
1969-1974 Chevrolet Blazer (2WD/4WD, All Engines)
1969-1987 Chevrolet K5 Blazer (4WD, All Engines)
1967-1981 Chevrolet G10 Van (RWD, All Engines)
1963-1987 GMC C15 / C1500 (2WD, All Engines)
1963-1987 GMC K15 / K1500 (4WD, All Engines)
1963-1987 GMC Suburban (2WD/4WD, All Engines)
1966-1981 GMC G15 / G1500 Van (RWD, All Engines)

Fitment Notes

Fits GM 8.875" 12-bolt truck differential with 30-spline axles and 3.73 and numerically higher gear ratios (Series 4 / thick carrier) only
Does not fit 2.76-3.42 carrier applications - a separate unit (YDGGM12T-3-30-1) is required for 3.42 and lower ratios
Does not fit the GM 12-bolt passenger car differential - truck and car versions use different carrier dimensions and are not interchangeable
1963-1964 applications require a 30-spline yoke - verify yoke spline count before installation
Synthetic gear oil is not recommended - use high-grade non-synthetic GL-5 gear oil with Yukon LSD additive (part OILADD) for proper clutch break-in and long-term smooth operation

Features

Yukon Dura Grip clutch-type limited slip differential delivering smooth yet aggressive traction across street, off-road, and performance driving conditions
High-strength nodular iron case for superior rigidity and long-term durability in heavy-duty truck applications
Forged 4320 chromoly spider gears machined for maximum tooth strength - significantly stronger than standard cast alternatives
Raybestos composite clutch pack design provides consistent, progressive lockup - smooth enough for daily street use without sacrificing performance
4-spring preload design ensures reliable and consistent clutch engagement under a wide range of load and terrain conditions
Fully rebuildable design - clutch packs and internals can be replaced independently, extending the service life of the unit
Assembled in the USA with computer-aided design and in-house quality lab testing for metallurgy, fit, and finish
Direct drop-in replacement for the GM 8.875" 12-bolt truck Series 4 open carrier in 30-spline, 3.73-and-up applications

Specifications

Differential Application: GM 8.875" 12-Bolt Truck (Rear)
Differential Type: Clutch-Type Limited Slip (Positraction)
Axle Spline Count: 30
Carrier Series: Series 4 (fits 3.73 and numerically higher gear ratios)
Case Material: Nodular Iron
Spider Gear Material: Forged 4320 Chromoly Steel
Clutch Type: Raybestos Composite
Spring Design: 4-Spring Preload
Ring Gear Diameter: 8.875"
Cover Bolts: 12
Assembly Location: USA
Position: Rear Differential

Included Components

1x Dura Grip Limited Slip Differential Carrier (fully assembled)

Product Description

The Yukon YDGGM12T-4-30-1 Dura Grip is a high-performance clutch-type limited slip differential built for the GM 8.875" 12-bolt truck rear axle with 30-spline axles and 3.73-and-up gear ratios. Compatible with classic Chevrolet and GMC trucks, Suburbans, vans, and Blazers from 1963 through 1987, this unit is the go-to positraction upgrade for builders looking to add reliable, street-friendly traction to one of GM's most respected heavy-duty truck axle platforms. Whether the application is a weekend trail rig, a classic work truck restore, or a performance street build, the Dura Grip delivers consistent torque transfer to both rear wheels without the harshness of a full locker.

The Dura Grip is built around a high-strength nodular iron case housing forged 4320 chromoly spider gears and a Raybestos composite clutch pack. The 4-spring preload design ensures smooth, progressive clutch engagement across a wide range of inputs - firm enough to deliver genuine traction improvement under hard acceleration or off-camber terrain, yet refined enough for daily driving on pavement. Unlike non-rebuildable units, the Dura Grip allows clutch pack replacement when worn, making it a long-term investment in the drivetrain rather than a disposable part.

Before ordering, confirm your GM 12-bolt truck differential uses 30-spline axle shafts and a Series 4 carrier (3.73 and numerically higher ratios). This unit does not fit the 2.76-3.42 carrier or the GM 12-bolt passenger car differential. Carrier bearings are sold separately and should be replaced at installation time for best results. Use high-grade non-synthetic GL-5 gear oil combined with Yukon LSD additive (part OILADD) - synthetic oil is not recommended and may cause noisy or erratic clutch operation.