Dynatrac assembles and fully...
Dynatrac assembles and fully welds every housing in-house. The company MIG welds its own heavy-duty boxed brackets to the housings with a precision jig.
Ring-and-pinion size is important...
Ring-and-pinion size is important when considering axle strength. Lower ratios mean fewer teeth on the pinion gear; this in turn makes for a weaker gearset. So bigger is better here. From left to right is the Dana 60 gearset found in our Pro-Rock axles, a Dana 44 set, and the dinky Dana 30 parts. It really depends on the weight of your rig and your driving style, but the 60 gears are good for tires up to 48 inches, the Dana 44 cogs are good for up to 35s, and the Dana 30 gears shouldn't be pushed by more than 33s.
The Pro-Rock centersection...
The Pro-Rock centersection was specially designed for more clearance while still making room for standard Dana 60 high-pinion gearsets and carriers. A bombproof cast-iron cover protects the Tractech Detroit Lockers on 5.38 gears and keeps the gear oil in.
From right to left there's...
From right to left there's the stub axle and U-joint from a Dana 44, 35-spline Dana 60, and our huge competition-alloy 40-spline stub and CTM U-joint. At the far left is a pseudo-secret monster stub axle and CV joint that Dynatrac is working on for a future project.
The flipside.
If you've been paying attention,...
If you've been paying attention, you've noticed that the 40-spline stubs are several inches shorter than the standard 35-spline parts. Dynatrac designed and is manufacturing its own stubby wheel hub (left) and chromoly forged spindle for use with narrow wheels or wheels with deep backspacing. The Ford "F450" unit-bearing assembly is in the middle, and a typical Dana 60 bearing hub is on the right.
For now only a driver is available...
For now only a driver is available for the 40-spline front axles. However, Dynatrac is working on its own low-profile locking hub design that can be used on the company's stubby hubs for both 35- and 40-spline stub axles. The new locking hub design may also be made available for other Dana 60 applications.
Dynatrac came up with a way...
Dynatrac came up with a way to use its standard large-bearing Ford housing end (top center) for both the 35-spline rear-axle-bearing assembly (left) and the 40-spline parts (right). These parts can help you convert a 30- or 35-spline semifloat rear axle to 40 splines without cutting or welding a thing.
The Dynatrac Pro-Rock 60 for...
The Dynatrac Pro-Rock 60 for our Unlimited came complete and bolts right to our Rubicon Express long-arm kit. We added Dynatrac's high-steer and track-bar kit to eliminate the possibility of any bumpsteer. These components allow you to retain the factory Pitman arm so you don't loose any turning radius, which is a common problem with dropped Pitman arms.
In the rear our Dynatrac axle retains the factory sway bar. It simply bolts right to the included boxed brackets, which are welded to the housing. With the 5 1/2-inch lift and high-pinion rearend we didn't even need a slip-yoke eliminator kit on our transfer case. It's practically a straight shot with no vibrations. However, we did need to shorten both the front and rear driveshafts to complete the axle swap.
Bend-Free Tubes
Larger tires work on your axlehousing similar to the way a longer breaker bar works on a rusty bolt. More leverage can bend the axletubes. A bent or overly flexed housing can lead to problems ranging from broken axleshafts, busted carriers, stripped gears, and leaky seals to premature failure of carrier and axle bearings, not to mention alignment problems. Original Wrangler Dana 30 front axlehousings are made from smallish 2 1/2-inch, 0.250-wall tube (A). Wrangler Rubicon Dana 44 fronts have the same small tubing as the Dana 30. Because of the potential abuse large tires and wheeling can put on a front housing, Dynatrac uses 3 1/8-inch, 0.500-wall tubing in Pro-Rock front axles (C). The frontend takes the brunt of the force when your Jeep hits an obstacle. The Pro-Rock tubing is nearly three times stronger than stock! The optional Dana 44 and Rubicon 44 rear housings have the same tubing as the notorious-for-bending Dana 35. They are made from 2 5/8-inch, 0.250-wall (B). Pro-Rock rearends get 3 1/8-inch, 0.313-wall tubing (D), which is almost twice as strong as the original Wrangler tubes.