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Filthy Motorsports: Store > GM 8.875" 12 Bolt
GM 8.875" (8.9") 12 Bolt Passenger (12P) and Truck (12T) Axle Parts and Upgrades

GM 12 Bolt Axle Models:

GM 12P (8.875") (Passenger Car)
GM 12T (8.875") (Truck)

Axle Specifications:

Ring Gear Diameter: 8.875
Diff Cover Bolts: 12
Ring Gear Bolts: 12
Axle Spline Count: 30
Axle Shaft Style: Semi-Floating
C-Clips: Yes
Pinion Support: No
Pinion Nut: 1-1/8"
Pinion Crush Sleeve: Yes
Carrier Breaks: P: 2.76 / 3.07
P: 3.73 / 3.90
T: 2.73 / 2.76
T: 3.42 / 3.73
Dropout Carrier: No

Torque Specifications:

Pinion Preload New: P: 14 to 19 in-lbs
T: 13 to 15 in-lbs
Pinion Preload Reused: P: 6 to 8 in-lbs
T: 6 to 7 in-lbs
Ring Gear Backlash: .006" to .010"
Ring Gear Bolt Torque: 55 ft-lbs
Carrier Bearing Caps: 60 ft-lbs

Popular Applications:

Chevy Bel Air 1964 - 1972 Rear
Chevy Camaro 1967 - 1972 Rear
Pontiac GTO 1970 - 1972 Rear
Chevy Nova 1964 - 1972 Rear
Chevy C10 / C15 1963 - 1987 Rear
Chevy Suburban 1963 - 1987 Rear
GMC K5 / K10 / K15 1963 - 1987 Rear

Axle Images:

Axle Details

The GM 8.875" (often rounded to 8.9") 12 Bolt axle is available in passenger car (GM 12P) and truck (GM 12T) rear axle configurations and features an 8.875" ring gear and 30 spline semi floating axle shafts. While both versions of the axle have similar specifications on paper, they do have unique differential carrier housings and most parts, including ring and pinion gears are not interchangeable. Because both axles are commonly referred to as GM 12 Bolt axles, it is important to know which version you have before ordering your parts. The easiest way to tell them apart is that the passenger car version has a perfectly round differential cover while the truck version has an irregular shape.

Note: This axle has a Carrier Break and gear changes may require a different carrier or thick gears.
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