The Dana 60 axle has become the de facto favorite among hard-core four-wheelers because the sheer size of the housing, the gears, the shafts, and the knuckles makes it virtually indestructible. However, the very thing that makes it most desirable is the one thing that makes it problematic: its size. The 60 housing is just so damn big and hangs down so far that axle clearance quickly becomes an issue.
Dynatrac introduced a shaved housing more than a year ago that offered four-wheelers greater clearance than the stock housing, but that still left a lot of casting to get caught in the rocks. So Jim McGean, the owner of Dynatrac, decided to design a Dana 60 housing that was smaller, meaner, and stronger than the original. Sound like a dream? Dynatrac calls it the Pro Rock 60.
So how did the they do it? Essentially, the engineers at Dynatrac reduced the total outside volume of the pumpkin below the axle centerline. At the same time, they increased the overall strength by using nodular iron that undergoes a heat-treating process at the foundry. Although smaller, the Pro Rock 60 is actually 40 percent stronger than a stock Dana 60. It offers 30 percent more ground clearance than a stock 60 housing - throughout the entire underside of the pumpkin - and actually has a 1/4-inch more clearance than a Dana 44.
One aspect that was of particular concern to Dynatrac during the design process was the ability of the new housing to deal with massive torque load. Big engines, low crawl ratios, tire resistance, and sheer weight create thousands of pounds of torque, which can cause weak housings to spread and distort. This typically leads to gear failure, differential failure, and so on. So Dynatrac engineered the Pro Rock 60 to comfortably deal with torque loads of more than 16,000 lb-ft.
Internally, the Pro Rock 60 still uses all of the off-the-shelf Dana 60 components, including the ring gear; none of the pieces are shaved or cut down. And to support the steep pinion angles that short-wheelbase vehicles have to contend with, Dynatrac engineered a unique oil-flow system to keep the gears well lubricated.
Sleeker, stronger, designed to survive...In the unforgiving world of axle evolution, the Pro Rock 60 is about to claw its way to the top of the food chain.