Diesel Power Articles
May 14 2021
IT'S FUNNY HOW ONE COMPONENT CAN MAKE OR BREAK THE IMAGE of a truck. When General Motors announced in 1991 thats its 1-ton pickups were switching to independent front suspension (IFS), there was a cry heard around the world. That cry was for the loss of the Dana 60 front axle that had been fitted to every four-wheel-drive 1-ton GM pickup since 1977. That cry still echoes to this day.
Ford and Dodge truck engineers must have rejoiced over the news. For in the heavy-duty-truck market, there's no subsitute for the simplicity, strength, and reliability of a solid axle. Maurice Rozo of Burbank, California, couldn't agree more. As a Chevy guy, he cringed at the loss of the Dana 60 axle in the GM lineup. Unlike the rest of us who could do nothing but complain about it, Maurice came up with a solution. He built his own GM solid axle suspension kit.
Working with a team of fabricators and designers at his shop Off Rod Unlimited (ORU), Maurice spec'd out a kit that would allow '92-and-newer GM 3/4-and 1-ton truck owners to install a Ford style Dana 60 front axle in their truck utilizing commonly available leaf springs. Off Road Unlimited made a name for itself offering this kit to the public, as well as developing other proven off road suspension, steering, and drivetrain products.
Over the years, most of the solid front axle GM trucks that you've seen on the road are either running ORU parts, or appear to have taken cues from the ORU kit. We've even seen Jim Carrey, the famous actor, driving a 3/4-ton solid axle GM truck that Off Road Unlimited built.
Recently, Off Road Unlimited has revised its solid axle swap kit to not only work with General Motors' latest GMT900 3/4-ton chassis, it's now developed a package that includes a four-link suspension and coilover shocks for '01-and-newer trucks.
It's had to believe, but Maurice's "Red Addiction" Chevy began life as a two-wheel-drive truck. After years of doing more solid axle swaps that anyone else, the one thing Maurice has never been completely satisfied with is the New Venture Gear transfer cases that the '01-and-newer Duramax trucks come with. Since Maurice knew he was going to ditch all the factory four-wheel-drive components, he figured he should just start with a two-wheel-drive truck instead.
Maurice ordered an '07 Silverado 2500HD with the LMM Duramax and Allison 1000 transmission. His solid axle upgrade kit is designed to work with both two and four-wheel drive GM truck frames, so that only left fitting the truck with a transfer case. For that, Maurice made a call to Advance Adapters, in Paso Robles, California, and ordered an Atlas II Transfer case with a 3:1 low-range.
Now, the Duramax's torque is transfered through the stock two-wheel-drive Allison 1000 six-speed transmission and sent back to a divorce-mounted Atlas transfer case. From there, the power is sent through a pair of driveshafts to the AAM 1150 rear and a custom-built Dynatrac Pro 60 front axle bolted in with ORU's latest four-link front suspension kit.
The gross axle weight rating (GAWR) of the GM 3/4-ton independent front suspension is 4,600 pounds. That means the front end is rated to support a little more than 2 tons, which gives and indication of the strength and durability of GM's IFS. A Dana 60 axle, on the other hand (one built to the specs of the Dynatrac Pro 60 in Maurice's truck), has a GAWR of more like 5,500 pounds giving it 900 pounds more capacity to take a pounding without breading so much as a sweat.
We can attest to the strenth of Maurice's 2500HD as we drove to 200 miles to our cover photo shoot, watched Maurice beat on it, and then drove it 200 miles back hone. Nothing we could do to the truck phased it in the least, and the truck came home needing only a new rear bumpstop, a fresh tank of fuel, and a good truck wash. Now that's what we call heavy duty!
A Dynatrac Pro 60 Front Axle with an ARB Air Locker, 4.56 gears, 35-spline axle shafts, and Off Road Unlimited ram-assisted crossover steering feeds Maurice's solid axle addiction.
The Pro 60 axle is located by Off Road Unlimited's new four-link solid axle conversion kit that features 2.5" King coilover shocks, hydraulic bumpstops, a sway bar, and limit straps.