Traction Action

Differentiating Wheel SpeedOne purpose of a differential is to allow for variations in drive-axle speed as the vehicle negotiates a corner. As the vehicle turns, the outside wheels are forced to travel a farther distance than the inside wheels. In order for a differential to complete this action smoothly, the outside axle must be able to rotate faster than the inside one. Allowing for differentiating axle speeds delivers a smooth, controlled turn. Once the turn is complete, the locking mechanism (if so equipped) inside the differential can then distribute power evenly to both axles for maximum traction and acceleration. Action of this procedure not only requires durability, but also a smooth, quiet operation.

Painted ring-gear teeth reveal the proper contact patch, allowing the builder to rotate the gears and read the markings on the ring gear teeth to determine how well the pinion and ring-gear are meshing together. The drive-side of the ring gear should show a darkened smudge slightly below the center point of the tooth.	A properly set ring and pinion will deliver its coast-side ring gear smudge slightly above the center point of the gear tooth.
Currie manufactures its own axles, cutting and drilling them with the proper bolt pattern, and then adding the appropriate number of splines. Before the splines are cut, each axle is hardened to a 57 on the Rockwell scale. This makes Currie axles 10 to 15 percent stronger than most factory axles.	Currie used its Ultimate-12 rearend cover to support the carrier main caps. When torque is applied, the carrier bearings try to move out of the caps and create cap lift, distorting the working internals. We pre-loaded each cap with 10 lb-ft of torque before locking the center studs in place.
Currie offers strengthened aftermarket race caps that are made from chromoly steel.	With 9-inch ends installed and the shock mounts relocated inward, our brake options are nearly endless. We could use Baer, Wilwood, Stainless Steel, OE Ford Explorer discs, and a whole lot more, but we chose a conventional drum. They only require 14-inch-or-larger wheels and use common 11x2 1/4-inch shoes.
A rearend is only as good as its surrounding parts, which is why Currie offers Currectrac adjustable-upper and rigid-lower control arms...	...The Johnny Joint technology acts like a Heim joint and allows as much as 30 degrees of articulation to cushion changing road conditions. Each piece is fully rebuildable and externally greaseable.

Fine Fitment The rearend industry can be tricky when it comes to vehicle fitment. Brake choices can be limited and troublesome as well. To remedy this, Currie has come up with several ways to make the rearend-swap experience easier. First, Currie formulated the Aftermarket Brake Configuration (ABC) Standard so that Currie and all other manufactures could work from a group of universal dimensions. This allows almost any housing and brake system to interchange. A standard 2.80-inch axle register will allow most drums and discs to slide easily over the axles. Along with the universal register size, Currie also implemented a 2 1/2-inch brake backspace dimension, as measured from axle-flange face to housing-flange face. This means numerous backing plates, calipers, and shock mounts can be used freely. Also part of the ABC Standard is stud choice and sizing. The axles can be drilled for most popular bolt pattern and stud sizes available (7/16-inch, 12 millimeter, 1/2x20x1 1/2-inch, or 1/2x20x3-inch). Depending on the wheel and brake system used, one of these studs will most likely do the job. Race applications are available in sizes as large as 5/8-inch. Once the brake system is configured around the ABC Standard, the housing and axle measurements can be accounted for. Currie measures its total housing distance as the distance between the two axle-wheel contact points. This way, the rearend and tire/wheel package will be sure to fit under the car. When measuring axle lengths, the distance from the tip of the splines to the face of the axle flange (axle-wheel contact point) is important to help ensure that the splines mesh properly into the differential when secured against the housing ends.