What if you could have the small size and low weight of a Dana 44 axle, and the brute-strength of a 35-spline Dana 60 axle? What if you wanted an ARB Air Locker to boot? Well, by September of this year you can, and we've installed them. ARB just came out with this prototype unit, which Jason Bunch of Tri County Gear is testing in his competition rockcrawling Jeep.
The basic concern of most 44 users is breaking the front U-joints, even with the high-grade fancy stuff. Conversely, a standard Dana 60 housing is big and heavy, adding weight and reducing ground clearance. Even the high-zoot aftermarket stuff is still bigger and heavier than a shaved 44, so the goal of ARB was to get a selectable locker with 11/2-inch 35-spline axleshafts. Of course, that means using 60 knuckles, end forgings, and joints, but CTM makes killer axles, joints, and outers that should never break in this application. In fact, we still don't know what the weak point will be, but can't wait to find out. Overall weight is about the same as a dialed-in 60, but the clearance is much better.
If you've been climbing over rocks instead of living under one, you know that an ARB Air Locker is a selectable locking differential, as opposed to an open diff. By using compressed air to engage the ARB, it changes from an open diff to a solid locked unit, capable of transmitting 100 percent of the torque to both axles when engaged, a true benefit when four-wheeling. Bunch has used the ARB units for years, and has been a proponent of light weight and strong components in his rigs since he started competing with his mighty four-cylinder Rock Star YJ Wrangler with a 30 front and 44 rear, spinning 37-inch Goodyears.
He's popped a few front axles with this setup and twisted a few rears, so the 35-spline conversion was a good idea, especially now that an Air Locker is available. We set up the front end with one of his custom 44 housings with high-steer 60 knuckles and killer CTM axleshafts. In the rear 44 we concluded with Warn alloy floater axles and Tri County Gear brakes. With 35-spline axles all around, we can't wait to see how they work on the competition circuit. Check out the highlights of what we found, and stay tuned for updates throughout the season.
The 44-35 big gun is on the left, with the standard style on the right. The new design offers timed-gear technology, which increases case and gear strength through better engagement. The case is also two pieces instead of three, but the biggest change is moving the air line to the left side of the case. With an improved seal arrangement, this is the toughest, most reliable ARB yet. | 
The consumer has no need to look inside the new ARB, but we just couldn't resist taking a peek. Timed-gear technology allows for full-tooth engagement of the side and spider gears. The 44-35 also has the improved bonded seal for reliability, and all these springs to force the clutch locking ring back. | 
Just to give you an idea of size, we stuck a stock 30-spline shaft and a 35-spline shaft into a housing. The standard Dana 30-spline is 1.31 inches in diameter, while the stock Dana 60 35-spline is 1.5 inches. This equates to a massive increase in strength, which is what's needed in today's hostile environment. |
To get these mongo 35-spline shafts inside a 44 carrier, the journal size was modified. The inner is bigger, and so is the outer diameter, which means special bearings. The outer diameter of the bearing race is the same as stock, so no housing modifications are needed. The new air line doesn't require notching the bearing cap either, so maximum strength is maintained. | 
If you want the best joints and shafts, then you better get some CTM 300Ms up front. These things are just huge, taking every inch of space available. To run this setup, Bunch made the housing with Dana 60 F-450 ends and his modified high-steer knuckles. These ends are much bigger than a 44, but ensure that the joints aren't going to go pop. | 
The outer splines of the CTM shafts (top) are the same as the 11/2-inch inner axle splines. Compare that with the stock 30-spline Dana 60 (center) and the weenie 19-spline stock outer of a Dana 44 (bottom). The unit-bearing/spindle for the knuckle needs to be bored out to use the big shaft, and fitted with an Oilite bushing. This stuff isn't cheap or easy, but you get what you pay for. |
The rear spindle needs to be upgraded as well. The Warn chromoly axleshafts and floater kit bolt onto many popular rear 44s, while some may take some machine work. Notice the size difference between the two spindles; the big one nearly fits over the stock 44 Warn spindle. | 
The rear installation is as simple as any ARB, and even the new air line on the left can bend around to fit the existing ARB fitting from an earlier installation. The new fitting features a rubber O-ring that is easier to install and service, and it reduces leakage as well. After the custom-splined Warn axles are slid into the ARB-fitted rear end, the hubs, rotors, and brakes are installed. The new hub can accommodate a set of locking Warn hubs, but we chose Warn drive flanges for maximum durability in the competition world. | 
All buttoned up, this old, shaved 44 housing fitted with the new 35-spline ARB looks as stealthy as ever. Except for the larger hubs and drive flanges, most people wouldn't even know what a big gun this setup really is. |