Installing a locker on a Super Duty
A few months back we introduced Plain Jane, a 2000 F-350 Super Duty with plain looks but a whole lot of personality. Original plans for Jane included using her as a tow rig, a camper, a capable 'wheeler, and a part-time daily driver. She is now nine months old and has racked up 19,000 miles, with about half of those miles pulling a 9000-pound trailer.
Because she lives on ranch land, her eight-foot bed has become handy for hauling everything from fence posts and tractor parts to wood pellets and trash cans. We also haven't been able to do as much serious 'wheeling with her as we'd like, but that's not to say she isn't up to it if asked, especially now. That's because to go along with her ready-for-anything Fabtech suspension and 36-inch Swampers (Four Wheeler March 2001), Jane now sports a pair of ARB Air Lockers and 4.30:1 gears in her diffs.
We chose ARBs because they offer the seamless driveability of an open diff and the grip of a full locker when ultimate traction is required. Remember, half of Jane's mileage has been pulling a trailer. An open-diff truck presents no surprises when pulling a load. Also, Jane lives in snow country. On icy roads, an open differential again offers no surprises. But if it snows too much, Jane will be the first one through the powder with her fully locked diffs. All we have to do is push a button.
When we installed 36-inch-tall tires in place of the stock 31s, we felt a power loss when pulling the trailer. Jane's big diesel engine didn't care much when the truck was empty, as the Power Stroke has power to spare. However, with a load, we were down a whole gear when towing in the mountains. Since we were pulling the diffs apart anyway to stick the ARBs in, now was the time for a gear swap. Jane came from the factory with 3.73 cogs. Some quick math revealed that with 36-inch tires, she'd be pretty close to stock with a set of 4.30s. So we made a call to Gary MacFadyen at West Coast Differentials (WCD) in Rancho Cordova, CA, and made an appointment for surgery.
WCD offers all the major brands of ring-and-pinion sets, as well as all the major aftermarket differentials. The company's huge warehouse stocks applications to fit just about anything that moves. Better yet, also housed in the same building is their Ring & Pinion Service, ready to install your new gears and diff. Best of all, WCD can ship its products anywhere in the world.