(Editor's note: As time permits, we'll focus our attention in each issue of FW on a single transmission, transfer case, or axle that was popular in a variety of past OE truck and Jeep applications, and which still holds appeal to truck builders today. We'll examine their componentry, talk to experts about their strengths, look for any obvious weak links, and recommend strong fixes when applicable. This month, we delve inside the popular Dana 44 and Dana 60 axles and see how they have improved in the aftermarket for wheelers.
Dana 44 and Dana 60: two of the axles coveted by wheelers in their quest for more robust rigs. While the stock or "junkyard" axles are desirable in their own right, companies such as Dynatrac in Huntington Beach, California, have been building brand new replacement axles for the four-wheeling community for over 15 years.
This is a stock Wrangler Rubicon...
This is a stock Wrangler Rubicon JK Dana 44 next to a Dynatrac ProRock 44 housing. Note that the ProRock has larger 3-inch axle tube bores.
Remember, the main job of an axle housing is to support the weight of vehicle, support the gears in mesh, and to maintain its shape under load. Stronger, performance-oriented axles are improved in these areas to offer better reliability and more confidence on the trail. We spent a day at Dynatrac to learn about the differences between the 44 and 60 to help you determine which axle might be right for you.
To better understand performance Dana axles, we'll first give you a brief history of the Dana 44 and Dana 60.
The Dana 44 was introduced after World War II and is commonly found under the front and rear of a wide variety of Jeeps, as well as International Harvester, Dodge, Studebaker and Ford trucks, and even under the rear of Isuzu Rodeos and Honda Passports up until the mid-'90s. It was offered in a centered or offset design, low or high pinion, and with either two-piece or flanged axleshafts.
This is the JK 44 housing...
This is the JK 44 housing close up. Take a look at the bolt ring (arrow) and webbing (arrow).
Starting in 1972, modern factory Dana 44s had 30-spine axleshafts with a thickness of 1.31 inches (earlier axles were 10- or 19-spline), although the rear next-generation Dana 44 found on the 2007-present Jeep Wrangler JK has 32-spline shafts. Axletube diameters range from 2.5 inches to 3 inches, and semi-floating models have a gross axle weight rating (GAWR) of 3,500 pounds and an output torque rating of 3,460 lb-ft. Ring gear diameter is 8.5 inches, while next-generation axles go up to 8.8 inches. The available gear spreads for the Dana 44 range from 2.72:1 to 5.89:1, and both five- and six-lug versions were used in OE applications.
The Dana 60, a heavier-duty axle than the Dana 44, was first used in the 1950s. It was the axle of choice under countless Dodge, Ford, GM, Studebaker, IH and Jeep 3/4-ton and 1-ton fullsize trucks, as well as Ramchargers and Trail Dusters with the 440ci V-8, and some heavy-duty 1/2-ton Ford and IH trucks. The Dana 60 can even be found underneath some performance Chrysler cars of the late '60s and early '70s, and was a very rare option on early-'60s CJs. Late-model Dana 60s are typically equipped with 30-spline axleshafts, in either a semi- or full-floating configuration; 35-spline axleshafts are found in some applications from the factory, but are the standard upgrade in the aftermarket.
Looking closely at the ProRock...
Looking closely at the ProRock 44 housing, you can see the extra material in the bolt ring (arrow) and webbing (arrow). These are just a couple of the key features that give the Dynatrac product its enhanced strength and rigidity.
Axletubes vary in size from 3 inches to 3.5 inches in diameter, and Dana lists the GAWR as 5,500 lb-ft for a semi-floating axle, while the full-floaters are good for 6,000 to 6,500 pounds. Both versions have a torque output rating of 5,500 lb-ft. The Dana 60's ring gear is 9.75 inches in diameter, and the available gear spread ranges from 3.31:1 to 7.17:1. There are both low- and high-pinion designs, and six- and eight-lug wheel bolt patterns.
Of course, these brief descriptions are generalizations about the axles and don't cover every configuration that was made. Both the Dana 44 and Dana 60 enjoy enormous aftermarket support and can be equipped with just about any traction aid available in the market, whether it is a tried and trued Detroit Locker, selectable locker, or a helical- or clutch/cone-style limited slip.