How do I identify a GM 12-bolt rear end?
The easiest way to identify a 12-bolt rearend is obviously by the 12 bolts holding the rear cover onto the axle housing. The pinion shaft on passenger-car differentials is 1-5/8-inch in diameter and the cover is oval, measuring 10-15/16-inches wide by 10-5/8-inches tall.
How do I identify my Chevy truck rear end?
All Chevrolet rear ends can be identified by comparing the gasket shape to an identification chart similar to the one found on Drivetrain’s differential identification page (see References). A visual chart of different GM/Chevrolet rear ends is found on Ring & Pinion’s differential types web page (see References).
How do I identify my GM rear differential?
Information about Differentials in GM vehicles can usually be obtained by looking at the RPO or “Regular Production Option” codes contained in the Service Parts Identification tag in the glovebox. Whenever possible, reference the tag numbers when ordering parts for your Differential.
How do I identify my GM rear axle?
Identify your GMC or Chevrolet rear end gear ratio by the RPO Codes, usually located on the placard labeled “Service Parts Identification” inside the drivers door panel or glove box.
How do I find out what rear end is in my truck?
To figure out exactly what axle you have, you can look for the Dana stamped bill of materials number. This stamped number can usually be found on the righthand side or on the longer axletube on the same side of the tube as the differential cover, facing the rear of the truck.
Is a GM 12-bolt rear end good?
When the 12-bolt rearend is properly assembled, it’s the strongest passenger-vehicle rearend Chevy ever produced. GM engineers designed the 12-bolt to be a durable piece that could handle the torque output of its big displacement engines.
How do I know if my rear end is Positraction?
If you can turn the wheel on your side while the other wheel is held still, the rear differential is not a Positraction unit. If you cannot turn the wheel on your side while the other person is holding their wheel in place, then the axle is a Positraction.
How do I know what rear differential I have?
Without an ID tag, differentials are identified by the number of cover bolts, the distinctive shape of the cover, the number of ring gear bolts, and ring gear diameter. They can also be identified by whether the center section is an integral or dropout design.
How much horsepower can a 12 bolt rear end hold?
In fact, they can stand up to around 800 hp, which is perfect for a street truck with some performance mods under the hood. Thirty-spline axles and a large ring gear help these rearends hold power. They also require less power to turn because of the height where the pinion gear contacts the ring gear.
What makes a GM 12 bolt rearend different?
To the contrary, aftermarket 30-spline differentials and axles are available. GM car and truck 12-bolt rearends are easily distinguishable by the cover shape. Most GM trucks from 1961 through 1972 used a rear suspension consisting of two trailing-arms with coil springs.
How did the Chevy 12 bolt get its name?
Chevy 12 Bolt Identification. The GM 12-bolt rear axle assembly receives its name due to having 12 bolts on the rear cover of the housing. This rear axle was available in GM’s high-performance intermediate cars, full-size vehicles and light-duty trucks.
When did GM stop using 10 bolt rearends?
After 1972, General Motors was only installing its 10-bolt rearend in cars, but the 12-bolt remained an option for trucks until 1987. When looking at a 12-bolt rearend, it is important to know that 12-bolt axle assemblies use different components for cars and trucks.
Where is the code ID on a 12 bolt?
Code ID 12-bolt axles can be identified by casting numbers on the bottom of the cast-iron center-section and on the front of the passenger side axle tube. This identifies the car make and model, gear ratio, date of casting and assembly and factory of origin.