Late Night Wrenching In the Hills of Virginia

What does a truck with 307,000 miles need? A rear locker.

byZach Bowman| PUBLISHED Jun 17, 2016 5:20 PM
Late Night Wrenching In the Hills of Virginia

The fog is thick and comes sulking through the open garage doors sometime past midnight. The Virginia mist mixes with the murky early morning hours and the rot smell of gear oil on concrete. I’m in Fincastle, doing little more than wringing my hands while a friend-of-a-friend dissects the rear differential on the Dodge. We’re six hours into a nine-hour job.

This started more than five months ago, long before we left Knoxville the first time. I was obsessed with outfitting the Dodge with the hardware it needed to get us into—and out of—the forgotten and empty places we planned to visit. I knew it was a big, heavy truck. I knew it would sink to its axles the first chance it got, bury itself on any terrain softer than groomed gravel. And while it rolled from the factory with a limited slip rear differential, the clutches had given out long before I got my hands on it.

I could have replaced them. Made do with the factory hardware and called it a day. Instead, I called ARB. The company has been making locking rear differentials for Toyotas and Land Cruisers for a generation. Back in 2009, they got into building units for three-quarter-ton General Motors and Dodge trucks. When I told them I was selling everything, moving my young family into my rig, and traveling the country for a year, they offered to send a passel of parts for us to try on.

Beth Bowman

A locker was not among the kit. It was backordered, and wouldn’t be available until long past our departure date. Last month, it showed up in Knoxville at last, just in time for us to swing by and grab it on our way through town. It arrived in a box about the size of a top hat, with the density of a neutron star. The shipping label said 52 pounds. We headed for Virginia with that pretty piece of iron sitting in the floorboard.

I’m a competent wrench, but nowhere near cozy enough with the mysteries of differential set-up to attempt the install. I needed help. Fortunately, I know people who know an ASE master tech with access to a well-stocked, clean, and organized shop.

Chris Frost has been the automotive service technology instructor at Botetourt Technical Education Center for 10 years, and when he’s not teaching the next generation of mechanics, he’s working on his own stable of loyal mules, from a notch-back Fox Body Mustang to a beautifully hammered Rawhide Edition CJ with a 351 under the hood. The school is a wonder, and Frost says the school board has been fantastic partner, ensuring that both the curriculum and the tools keep pace with changing automotive tech.

He’s quiet at first. Tall and thin, with sharp brown eyes that watch my movements. A decade of teaching high schoolers how to keep from losing a finger in a functioning auto shop has taught him how to gauge competence with a glance. I drop the sway bar and crack the diff cover to drain the fluid while he gathers tools for the job. We pull the axles and the driveshaft. He sets up his dial indicator and takes the measurements he’ll need to reinstall the differential with the new carrier.

Beth Bowman

It’s a muggy evening, and the sky turns dark and heavy with a low brawler of a thunderstorm as we unbolt the old carrier. Joe Harwell, the mutual acquaintance that put me in touch with Frost, shows up just in time to get soaked and help lug the chunk to a workbench. The rain falls in sheets outside, flooding the parking lot while lighting cracks across the clouds. The whole thing feels more than a little Shelley.

Frost is patient. Diligent. Properly obsessive about cleaning and inspecting the old parts. He pulls the carrier bearings, the ring gear, and tone ring. Looks it all over and deems it serviceable. He loosens up the longer we work, laughing and cutting jokes.

We’re left with a bare carrier. Frost digs up one from a Dana 30, the ubiquitous front axle from a long line of hardcore ‘70s off-roaders. Compared to the monstrosity from the AAM 11.5 axle in the back of the Dodge, it looks like a toy.

The new piece from ARB is beautiful. No other word for it. It’s a bare chunk of gorgeous, glossy iron. The company says it’s five times stronger than the factory differential, designed to stand up to the repeated hammerings of diesel drag trucks and county fair sled pulls. I can’t stare at it for too long. It gives me dark ideas.

Beth Bowman

We send Harwell out for pizza, and brake cleaner. It’s dark and getting darker, and we’re all starving from having skipped a proper dinner. We pound waters and slices of pizza dripping with a soup of toppings, cheese, and tomato sauce. It’s heaven.

It’s been four months or better since I’ve put my hand to a task like this. Bent to it, lost hours in it. It’s a welcome departure from the echo of worries in my head, a blissful mechanical mediation—a functional exercise in the clear procedure of the present. It’s past nine when a third friend, Gavin Worley, shows up to lend another hand.

It takes a spell to drill the cast iron housing. An inch thick where the air line leaves the differential and runs to the compressor. It’s awkward space, too, tucked up above the axle and between the spare tire, twisted at just such an angle so that the drill bites and threatens to snap my thumb a dozen times. I’m sweating and wore thin, an old injury making my shoulder sing in its socket, but I get the better of it. When I’m through, Frost cleans out the housing one more time. We douse the bearings in gear oil and load the new assembly in place.

Beth Bowman

Harwell and Frost finish setting up the gear while Gavin and I turn our attention to plumbing the line and installing the necessary switches in the dash. I’d already gone through the hassle of installing the compressor during a lull back in Grand Junction, and, in a rare moment of prescience, managed not to bury the wiring harness in the depths of the dash. After a brief and exhausting fight with the driveshaft, we were ready to test the thing.

I fire up the compressor, let it fill the auxiliary three-gallon air tank, then click the locker on. There's a rush of air leaks, the hissing noise of compressed air escaping where it shouldn’t, followed by the most beautifully industrial closure. It’s the sound of two wide hickory blocks dropping together. The sound of slabs of iron locking the rear axles together. Everybody in the room grins like a fool.

It’d been a long minute since I’d seen the south side of 3:00 AM, but that’s when we wrap. Put away the tools and clean the floor. I ask Frost how much I owed him for the agony.

“Nothing,” he said. “It was a fun install. Always wanted to do one.”

It’s hard to fathom that kind of generosity. That kind of help for a perfect stranger. I shake the man’s hand, glad to know another friend in this world. Glad to see the bent parts of myself mirrored back in his eyes. Joe heads for home in Lynchburg while Gavin and I point ourselves north, rolling through that thick mist towards a shower, a few thin hours of sleep.