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The Eaton Detroit Truetrac Differential (Part #912A556) is a proven, helical-gear limited-slip differential designed for GM 8.5-inch (10-bolt) axles with 28-spline shafts and 2.73 & up gear ratios. Built for balanced performance and reliability, the Truetrac automatically distributes torque to the wheel with the most traction—improving control, handling, and stability in both on-road and off-road conditions.
With its all-gear design, the Truetrac operates quietly and requires no maintenance or special additives. It’s a durable and efficient upgrade for muscle cars, classic restorations, and light trucks looking for enhanced traction without compromising street manners.
Note: All Eaton differentials for GM 8.5"/8.6" axles require special bearings.
Pre-1999 (Small bearing bore 2.89"): Use bearing LM102949 and race LM102911.
1999–2013 (Large bearing bore 3.06"): Use bearing LM603049 and race LM603012.
Manual locking hubs are recommended for front axle installations.
Features:
Helical-gear, torque-biasing design for automatic traction transfer
Maintenance-free—no clutch packs, friction plates, or additives required
All-gear construction for superior strength and long-term durability
Quiet and smooth operation for both street and performance driving
Designed for GM 8.5" 10-bolt axles with 28-spline shafts and 2.73 & up gear ratios
Ideal for restoration, towing, and high-performance applications
| Specification | Detail |
|---|---|
| Part Number | 912A556 |
| Differential Type | Limited Slip (LSD) |
| Axle Model | GM 8.5" / 10-Bolt |
| Spline Count | 28 |
| Ring Gear Ratio | 2.73 & Up |
| Ring Gear Size | 8.5 in |
| Axle Shaft Diameter | 1.2 in |
| Weight | 26.17 lb |
| Bearing Note | Requires special bearings (see catalog notes) |
| Front Axle Note | Manual locking hubs recommended |
Fitment:
Compatible with GM 8.5-inch 10-bolt rear axles, commonly used in classic GM cars and light-duty trucks.
1971–1989: GM, Chevrolet, Pontiac, Buick, Oldsmobile Passenger Cars – Rear 10-Bolt C-Clip (2.73 & Up)
1972–1989: GM Half-Ton Trucks – Rear 10-Bolt C-Clip (2.73 & Up)
1978–1989: GM ¾-Ton Trucks and Vans – Rear 10-Bolt C-Clip (2.73 & Up)
Ideal Usage:
On Road: Street & Muscle, Restoration, Drag Racing, Circle Track, Work Truck / Towing
Off-Road: Light Trail, Sand Sports, Work Truck / Towing
This Part Fits:
| Year | Make | Model | Submodel |
|---|---|---|---|
| 1973-1975 | Buick | Apollo | Base |
| 1975 | Buick | Apollo | SR |
| 1971-1973 | Buick | Centurion | Base |
| 1973-1977,1980-1981 | Buick | Century | Base |
| 1975-1979,1982-1989 | Buick | Century | Custom |
| 1980-1981,1984 | Buick | Century | Estate |
| 1985-1989 | Buick | Century | Estate Wagon |
| 1976 | Buick | Century | Indianapolis 500 Pace Car |
| 1978-1989 | Buick | Century | Limited |
| 1973-1975 | Buick | Century | Luxus |
| 1984 | Buick | Century | Olympia Limited |
| 1975-1979 | Buick | Century | Special |
| 1978-1981 | Buick | Century | Sport |
| 1983-1986 | Buick | Century | T-Type |
| 1971-1974,1976-1979 | Buick | Electra | 225 |
| 1971-1974 | Buick | Electra | 225 Custom |
| 1974 | Buick | Electra | 225 Limited |
| 1973 | Buick | Electra | Base |
| 1975 | Buick | Electra | Custom |
| 1980-1989 | Buick | Electra | Estate Wagon |
| 1975-1989 | Buick | Electra | Limited |
| 1978-1989 | Buick | Electra | Park Avenue |
| 1989 | Buick | Electra | Park Avenue Ultra |
| 1985-1989 | Buick | Electra | T-Type |
| 1971-1983 | Buick | Estate Wagon | Base |
| 1971-1972 | Buick | GS | Base |
| 1971-1972 | Buick | GS 455 | Base |
| 1971-1981,1987-1989 | Buick | LeSabre | Base |
| 1985 | Buick | LeSabre | Collector's Edition |
| 1971-1973,1975-1978,1982-1989 | Buick | LeSabre | Custom |
| 1977 | Buick | LeSabre | Custom Sport |
| 1985-1989 | Buick | LeSabre | Estate Wagon |
| 1979-1989 | Buick | LeSabre | Limited |
| 1982 | Buick | LeSabre | Limited Edition F/E |
| 1974 | Buick | LeSabre | Luxus |
| 1978-1981 | Buick | LeSabre | Sport |
| 1987 | Buick | LeSabre | T-Type |
| 1976-1979 | Buick | Opel | Base |
| 1977-1979 | Buick | Opel | Deluxe |
| 1978-1979 | Buick | Opel | Sport |
| 1988-1989 | Buick | Reatta | Base |
| 1973-1987 | Buick | Regal | Base |
| 1988-1989 | Buick | Regal | Custom |
| 1982-1983 | Buick | Regal | Estate Wagon |
| 1987 | Buick | Regal | GNX |
| 1989 | Buick | Regal | Gran Sport |
| 1984-1987 | Buick | Regal | Grand National |
| 1978-1989 | Buick | Regal | Limited |
| 1982 | Buick | Regal | Limited Turbo |
| 1978-1982 | Buick | Regal | Sport |
| 1976-1977 | Buick | Regal | SR |
| 1983-1986 | Buick | Regal | T-Type |
| 1971-1985 | Buick | Riviera | Base |
| 1971 | Buick | Riviera | Gran Sport |
| 1975 | Buick | Riviera | GS |
| 1982 | Buick | Riviera | Limited Edition |
| 1983-1989 | Buick | Riviera | Luxury |
| 1978 | Buick | Riviera | LXXV Anniversary Edition |
| 1979-1980 | Buick | Riviera | S |
| 1976 | Buick | Riviera | Sport |
| 1976 | Buick | Riviera | SR |
| 1981-1989 | Buick | Riviera | T-Type |
| 1983 | Buick | Riviera | XX Anniversary Edition |
| 1975-1980 | Buick | Skyhawk | Base |
| 1982-1989 | Buick | Skyhawk | Custom |
| 1980 | Buick | Skyhawk | Designers' Accent Edition |
| 1982-1987 | Buick | Skyhawk | Limited |
| 1979-1980 | Buick | Skyhawk | Road Hawk |
| 1975-1980 | Buick | Skyhawk | S |
| 1988-1989 | Buick | Skyhawk | SE |
| 1986-1987 | Buick | Skyhawk | Sport |
| 1983-1987 | Buick | Skyhawk | T-Type |
| 1972 | Buick | Skylark | 350 |
| 1971-1972,1975-1982 | Buick | Skylark | Base |
| 1971-1972,1978-1979,1983-1989 | Buick | Skylark | Custom |
| 1980-1989 | Buick | Skylark | Limited |
| 1976-1979 | Buick | Skylark | S |
| 1978,1980-1983 | Buick | Skylark | Sport |
| 1975-1977 | Buick | Skylark | SR |
| 1983-1984 | Buick | Skylark | T-Type |
| 1986-1987 | Buick | Somerset | Custom |
| 1986-1987 | Buick | Somerset | Limited |
| 1986 | Buick | Somerset | T-Type |
| 1985 | Buick | Somerset Regal | Base |
| 1985 | Buick | Somerset Regal | Limited |
| 1971-1972 | Buick | Sportwagon | Base |
| 1971-1975 | Chevrolet | Bel Air | Base |
| 1987-1989 | Chevrolet | Beretta | Base |
| 1989 | Chevrolet | Beretta | GT |
| 1971-1972 | Chevrolet | Biscayne | Base |
| 1971-1972 | Chevrolet | Brookwood | Base |
| 1971-1980,1988 | Chevrolet | Camaro | Base |
| 1979-1986 | Chevrolet | Camaro | Berlinetta |
| 1985-1989 | Chevrolet | Camaro | Iroc-Z |
| 1973-1978,1987 | Chevrolet | Camaro | LT |
| 1976-1978 | Chevrolet | Camaro | LT Rally Sport |
| 1976-1980 | Chevrolet | Camaro | Rally Sport |
| 1971-1973,1975,1989 | Chevrolet | Camaro | RS |
| 1981-1987 | Chevrolet | Camaro | Sport |
| 1971-1972 | Chevrolet | Camaro | SS |
| 1971-1974,1977-1987 | Chevrolet | Camaro | Z28 |
| 1982 | Chevrolet | Camaro | Z28 Indianapolis 500 Pace Car |
| 1971-1972,1986-1989 | Chevrolet | Caprice | Base |
| 1973-1989 | Chevrolet | Caprice | Classic |
| 1986-1989 | Chevrolet | Caprice | Classic Brougham |
| 1976-1978,1981-1982 | Chevrolet | Caprice | Classic Estate |
| 1976-1981 | Chevrolet | Caprice | Classic Landau |
| 1987-1989 | Chevrolet | Caprice | Classic LS Brougham |
| 1975-1976,1979-1980 | Chevrolet | Caprice | Classic Sport |
| 1973-1974 | Chevrolet | Caprice | Estate |
| 1975 | Chevrolet | Caprice | Estate Wagon |
| 1982-1989 | Chevrolet | Cavalier | Base |
| 1982 | Chevrolet | Cavalier | Cadet |
| 1982-1986 | Chevrolet | Cavalier | CL |
| 1983-1987 | Chevrolet | Cavalier | CS |
| 1984 | Chevrolet | Cavalier | Olympic |
| 1986-1989 | Chevrolet | Cavalier | RS |
| 1984-1985 | Chevrolet | Cavalier | Type-10 |
| 1988-1989 | Chevrolet | Cavalier | VL |
| 1986-1989 | Chevrolet | Cavalier | Z24 |
| 1982-1989 | Chevrolet | Celebrity | Base |
| 1982-1983,1989 | Chevrolet | Celebrity | CL |
| 1985 | Chevrolet | Celebrity | Classic |
| 1982 | Chevrolet | Celebrity | CS |
| 1985-1987 | Chevrolet | Celebrity | Estate |
| 1984-1989 | Chevrolet | Celebrity | Eurosport |
| 1971-1972 | Chevrolet | Chevelle | Base |
| 1971-1972 | Chevrolet | Chevelle | Concours |
| 1971-1972 | Chevrolet | Chevelle | Concours Estate |
| 1973 | Chevrolet | Chevelle | Deluxe |
| 1971-1972 | Chevrolet | Chevelle | Greenbrier |
| 1971-1972 | Chevrolet | Chevelle | Malibu |
| 1971-1972 | Chevrolet | Chevelle | Nomad |
| 1971-1972 | Chevrolet | Chevelle | SS |
| 1976-1985 | Chevrolet | Chevette | Base |
| 1984-1987 | Chevrolet | Chevette | CS |
| 1982 | Chevrolet | Chevette | Diesel |
| 1977 | Chevrolet | Chevette | Rally Sport |
| 1976 | Chevrolet | Chevette | Rallye |
| 1983 | Chevrolet | Chevette | S |
| 1977 | Chevrolet | Chevette | Sandpiper |
| 1976-1983 | Chevrolet | Chevette | Scooter |
| 1976 | Chevrolet | Chevette | Sport |
| 1976 | Chevrolet | Chevette | Woody |
| 1980-1983 | Chevrolet | Citation | Base |
| 1980 | Chevrolet | Citation | Club |
| 1980 | Chevrolet | Citation | Custom |
| 1980-1983 | Chevrolet | Citation | X-11 |
| 1984-1985 | Chevrolet | Citation II | Base |
| 1984-1985 | Chevrolet | Citation II | X-11 |
| 1987-1989 | Chevrolet | Corsica | Base |
| 1987-1988 | Chevrolet | Corsica | LT |
| 1989 | Chevrolet | Corsica | LTZ |
| 1988 | Chevrolet | Corvette | 35th Anniversary Edition |
| 1971-1974,1977-1982,1984-1989 | Chevrolet | Corvette | Base |
| 1982 | Chevrolet | Corvette | Collector's Edition |
| 1978,1986 | Chevrolet | Corvette | Indianapolis 500 Pace Car |
| 1978 | Chevrolet | Corvette | Silver Anniversary Edition |
| 1975-1976 | Chevrolet | Corvette | Stingray |
| 1971-1985 | Chevrolet | Impala | Base |
| 1975-1977 | Chevrolet | Impala | Custom |
| 1976 | Chevrolet | Impala | Custom Landau |
| 1981-1982 | Chevrolet | Impala | Estate |
| 1977-1979 | Chevrolet | Impala | Landau |
| 1976 | Chevrolet | Impala | S |
| 1975-1976,1979-1980 | Chevrolet | Impala | Sport |
| 1971-1972 | Chevrolet | Kingswood | Base |
| 1971-1972 | Chevrolet | Kingswood | Estate |
| 1973-1975 | Chevrolet | Laguna | Base |
| 1973 | Chevrolet | Laguna | Estate |
| 1975-1976 | Chevrolet | Laguna | S3 |
| 1974 | Chevrolet | Laguna | Type S-3 |
| 1973-1981 | Chevrolet | Malibu | Base |
| 1974-1983 | Chevrolet | Malibu | Classic |
| 1975-1976,1978-1980 | Chevrolet | Malibu | Classic Estate |
| 1976-1981 | Chevrolet | Malibu | Classic Landau |
| 1977,1979-1980 | Chevrolet | Malibu | Classic Sport |
| 1973-1974,1979-1980 | Chevrolet | Malibu | Estate |
| 1976,1979 | Chevrolet | Malibu | Landau |
| 1979 | Chevrolet | Malibu | Police |
| 1977,1979-1980 | Chevrolet | Malibu | Sport |
| 1971-1974,1979,1981-1988 | Chevrolet | Monte Carlo | Base |
| 1983 | Chevrolet | Monte Carlo | CL |
| 1973-1974,1976,1978-1981 | Chevrolet | Monte Carlo | Landau |
| 1986-1988 | Chevrolet | Monte Carlo | LS |
| 1973,1975-1977 | Chevrolet | Monte Carlo | S |
| 1978,1980 | Chevrolet | Monte Carlo | Sport |
| 1983-1988 | Chevrolet | Monte Carlo | SS |
| 1975-1980 | Chevrolet | Monza | 2+2 |
| 1978-1980 | Chevrolet | Monza | 2+2 Sport |
| 1976-1980 | Chevrolet | Monza | 2+2 Spyder |
| 1976,1978-1980 | Chevrolet | Monza | Base |
| 1977 | Chevrolet | Monza | Mirage |
| 1975,1978-1979 | Chevrolet | Monza | S |
| 1978 | Chevrolet | Monza | Sport |
| 1980 | Chevrolet | Monza | Spyder |
| 1976-1977 | Chevrolet | Monza | Towne Coupe |
| 1976-1977 | Chevrolet | Monza | Towne Coupe Cabriolet |
| 1976-1977 | Chevrolet | Monza | Towne Coupe Sport |
| 1976 | Chevrolet | Monza | Towne Coupe Spyder |
We are open Monday-Friday from 8am-6pm EST
Yes, customers located in and around the the Piedmont area are welcome to pick up their items from our retail location during normal business hours. Our address is:
Elite Race Fab
1514 Holbrook St Suite D-F
Greensboro, NC 27403
Elite Race Fab offers free ground shipping & handling to our retail customers within the lower 48 contiguous United States on most orders totaling $159.99 and higher, when the item being purchased is not a Freight/LTL item! Orders under $159.99 will be subject to a nominal $13.99 Flat shipping charge. Some exceptions and/or exclusions apply, in those scenarios you will be advised of any additional charges in the item details/description stating shipping exclussions/freight shipping required etc.
In regards to expedited and international shipping each order will need to be quoted on a case by case basis. You can obtain a quote two ways:
- From your shopping cart select "Request a Quote" prior to placing your order. We will review your proposed order and promptly respond with shipping estimates.
- Complete your order ahead of time indicating either expedited or international shipping during the checkout process. We will promptly determine shipping rates for your order and email you for approval and additional payment.
-Give us a call and we can ensure your item is shipped right then, to ensure you have it in time for your deadline.
We have been committed to offering all of our customers the lowest pricing throughout our website day in and day out. We value your business so much that we go a step further than our competitors. We use a third party software that proactively monitors all our competitor's websites/pricing so that we can make adjustments accordingly if needed to have the lowest prices. Thats right, no need to spend hours searching for the lowest prices, as ours will be the lowest.
As far as price matching, we dont want to write a check we cant cash, but we certainly want to earn your business. With that said, we will go above and beyond to match our competitor's pricing when it is needed. Simply email us, click the live contact button, or give us a call and be sure to have a link to our competitor's site and please factor in any shipping and handling their website will be charging. We will then ensure you get the lowest price, and either match or beat their pricing.
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