Comparing Jeep Axles and Differentials
For reference, we're not just talking about axles. We're talking about differentials. Technically, the axle is the shaft that connects to the wheel and rotates with the gearing inside the differential. For instance, here is a typical example of a rear axle made by Omix for a Dana 35, Part 5012820AA. Note the studs at one end to bolt the wheel on. The Omix part is more of a kit, and includes a new axle bearing and seal. For the most part, visually, all axles look about the same in a photograph. The lengths, thickness, size, and spline count will differ from axle to axle. The differential housing has two axles (a left and a right). Typically they are about the same, except the length can be different (but on some vehicles, they can be the same exact part, left and right). Jeep has used a variety of differentials over the years, and they can look almost the same, but since you can buy the entire housing, or even a complete differential setup, it's easy to see the differences once you look.
Getting to Know the Jeep Differentials
Dana 30 differentials are used in most Jeeps. From the CJ-series (CJ5, CJ7, CJ8 Scrambler) to the YJ, TJ Wranglers, and even XJ Cherokees. These axles would be made for open end steering, meaning, they allow for front spindles and parts that allow the vehicle to turn. They have 10 bolts on the cover plate. The stock shafts typically have 27 splines (though you can count yours to verify of course). Here above is a picture of a cover from ARB, Part ARB-0750002B. Notice it has ten holes (the one larger whole near the bottom is to drain the housing of oil without moving the cover). To get an idea of the whole differential end to end, here's a TeraFlex Tera 30 Heavy Duty Front Replacement Axle Housing (Part TF-3503004). Note how the ends are made to accept spindles.
Getting a Look at Jeep Dana 44s front and Rear
The Dana 44 has been used on the front and rear of Jeeps. They're more common on the rear than the front though over the years. Except for some interior components, and other obvious minor differences on the outside with brackets and such, they are almost the same. The fronts have the changes needed for spindles, while the rear ones allow for the axles to accept bolt-on wheels. Here's a Dana 44 front differential below, a G2 Front Dana 44 Assembly, Part D44TJFA456. Note the way the ends are made for spindles.
Here's a front Dana 44 cover from Rancho, an RS-6209. The Dana 44s have 10 bolt holes. The large bolt hole on this style is for filling the differential with oil. Here is a cover for a rear Dana 44 by Spicer. Part SPC-42960-1. In some cases, the cover will fit front and rear, depending on the manufacturer. For comparison, here is a rear MOPAR Dana 44 Assembly, Part P5153826AB-M. At this point, we've covered the some of the popular and more common differentials that were stock on Jeeps. There are some others, like the front Dana 25 or 27's, used on older Jeeps, 1986 and older, back to the 1941 Willys. Or the AMC Model 20 rear differentials that were used during the time when AMC owned Jeep, around 1976 to 1986. If you would like to see blow-up parts diagrams of all the smaller parts inside a differential, we have those broken down by the different models to make them easy to see and order parts from.
Jeep differential diagrams includes:
- Dana 30 Front
- Dana 44 Front
- Dana 25 & 27 Front
- Dana 35 Rear
- Dana 44 Rear
- Chrysler 8.25 Rear
- AMC 20 Rear
- Dana 35/194mm Rear
- Dana 27 Rear
What kind of axles do you have and what kind of driving are you doing?