I've had 4.56 gears, an open front differential, and an automatic locking rear differential for a while now, and it's worked out well.
At the same time, there was room for improvement. The 4.56 gears worked great with 33's, but when the 35's were bolted on, the motor needed a little more oomph from a dead stop. As much as I liked the open front diff and the automatic rear, there were times when a locking front differential would have made things easier on the trail. Astern, I really liked the way the automatic locker was both automatic and self-contained: a true no-hassle traction device. In the dirt, the automatic locker provided no-hassle, rock-solid traction.
Why change differentials? The automatic locker can't be shut off. I don't mind the handling idiosyncracies on the pavement. I've learned what they are and I can sometimes use them to my advantage. The traction in the dirt was always worth the quirky handling on the street. What I don't like is the shorter life that my rear tires always lead.
ARB Air Lockers are the answer. They're a totally open, transparent, pavement-and-tire-friendly differential until you add the requisite air pressure. Then they're totally locked. Locked in unison with both wheels turning at the same rate.
Yukon Gears were selected, as the brand has consistent high quality and offers a wide range of applications. Along with ring and pinion sets, Yukon Gear & Axle offers installation kits to go with the gears.
My rear axle is a custom Currie 9-inch, so Currie Enterprises was the intuitive choice to build the new third member. I have another truck project that uses a 9-inch with 4.56 gears and an automatic locker, so my existing third member will make a great spare for that project truck.
At Currie's new shop in Corona, California, technician Nicolas Serrato used tools and talents to meld a Currie 9-Plus gear case with the Air Locker, the Yukon gears, and the installation kit. "Nico" also installed a Currie Daytona-style aluminum pinion support and an input flange instead of a traditional yoke. The input flange is very cool, as it allows retention of the stock driveshaft.
In the photo, Nico is using an electric drill to spin the gears, checking the contact pattern. We'll be documenting this more in print, along with the front diff and gear swap.
Nope, there's nothing quite so constant as change.