Q. Are all GM 12-bolt rear ends the same?
They are not interchangeable. That doesn’t mean the truck rearend is not capable of receiving performance upgrades. 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.
Q. How can you tell if a 12-bolt posi 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.
Q. 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.
Q. Is limited slip differential the same as Positraction?
The limited-slip differential is similar to the positraction differential, but allows the wheel with traction to have only a limited amount of greater power than the wheel that is slipping. A limited-slip differential will prevent the tire with less traction from separately spinning.
Q. 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.
Q. 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.
Q. Is a Chevy 12-bolt rear end good?
Q. What is the strongest rear end?
The 9-inch Ford Rearend is the Strongest Rearend Out There—It’s All Due to “Hypoid Distance” 1] The 9-inch Ford has no differential case gear-ratio range restrictions; one differential accepts all gear ratios from the 2s through the 6s.
Q. How do you know if you have Positraction?
Shift your transmission into neutral so that the rear wheels rotate freely. Grasp one rear wheel, turn it and observe the other rear wheel. If the other rear wheel turns in the same direction, there is positraction.
Q. What cars came with Positraction?
What cars came with posi traction? GM has offered Positraction rear ends since 1957, and its 8.875-inch 12-bolt Positraction was most popular in Chevrolet passenger cars from 1965 to 1972. Pontiac offered a version of a Positraction unit, called Safe-T-Track, as an option on vehicles including the 1963 Pontiac Tempest.
Q. Is posi limited slip?
TOM: Actually, Jeannie, “posi-traction” is just Chevrolet’s name for limited slip differential on passenger cars. But because of the way the differential works, when one wheel starts to slip, ALL of the power is then delivered to THAT wheel. That doesn’t help you much if that wheel is stuck on snow or ice.
Q. What does 12-bolt posi mean?
The 12-bolt integral design features a carrier case and pinion support that are part of the rearend housing, while the 9-inch employs a drop-out third member that takes advantage of an independent carrier case and pinion support that bolts into the rearend housing.
Q. 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.
Q. 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.
Q. Which is the top of the line GM rearend?
When it comes to GM muscle car purists – and enthusiasts searching for the ultimate Chevrolet rearend – the 12-bolt rearend is considered the top of the heap in regards to a high-performance axle assembly.
Q. Can You rebuild a GM Posi clutch differential?
GM and Eaton clutch type posi differentials are fully rebuildable with several companies making replacement and upgraded clutch packs. Preload springs and pinion gears are also available.
