1990 Chevy 3500 Combines 4WD, an LB7 Duramax and 35-Inch Tires

Brandon Shaner’s 1990 Chevrolet 3500 now pairs a rebuilt LB7 Duramax with four-wheel drive, but the build’s appeal lies in how it balances working-truck hardware with the old Chevy’s worn-in character. The Indiana owner kept the original patina and much of the cabin intact, while adapting the chassis and drivetrain around a diesel sourced in pieces.

The truck started as a two-wheel-drive crew cab with a 454-cubic-inch V8 that barely ran, leaked fuel and overheated. Shaner, a General Motors dealership technician, had it running properly within a day of bringing it home. He drove it for two months before converting it to four-wheel drive, then spent six years gathering parts for the diesel installation.

A long route to the Duramax

Shaner’s familiarity with Chevrolet trucks runs deep: he also owns a 1985 C10 and a 1985 K10, and his family has more than 20 Duramax-powered vehicles. Sled pulling is another family interest, so the combination of diesel power and four-wheel drive fits a well-established pattern for them.

The project paused after Shaner was diagnosed with non-Hodgkin lymphoma in 2020 and underwent chemotherapy and radiation. He reports that he’s doing well today. When he returned to the build, the cost of Duramax drivetrains had doubled in the post-COVID period, so he found another route: rebuilding a 2003 LB7 given to him by his brother-in-law.

The engine arrived disassembled, with its components in two boxes and the remaining parts on a skid. A broken valve spring had damaged the number one piston, but the block was intact. That gave Shaner a usable foundation for a rebuild tailored to the truck.

Built around a repaired LB7

The fuel and air upgrades include S&S Diesel Motorsport SAC45 injectors, which provide a 45 percent increase in fuel volume, and a Dan’s Diesel Performance Stage 2 turbo with a 64mm compressor. A Wehrli Custom Fab four-inch turbo horn is specified to flow 40 percent better than stock. The article gives no finished horsepower or torque figures, so the hardware list offers the clearest picture of the engine’s setup.

Precision Fabrication Plus engine mounts secure the Duramax. Cooling comes from a Power Cool Manufacturing aluminum radiator and two SPAL electric fans. Ken Wolkens modified the 2003 Duramax wiring harness for the installation, while MTKB Racing tuned the engine control module. The exhaust is a single four-inch system ending in a six-inch tip; much of it came from a pulling truck previously owned by Shaner’s father.

The fuel system uses a 25-gallon tank and an AirDog 165-gallon-per-hour lift pump. That capacity is the pump’s stated flow rating, not a measure of the truck’s fuel economy. No mileage figure is reported, though improved economy was part of Shaner’s goal for the truck.

A 2003 Allison 1000 automatic carries power through a custom crossmember. Shaner’s father and brother, both Allison technicians, rebuilt the transmission, which includes a Goerend Triple Disc torque converter. The transfer case is also from a 2003 truck: an NP248 two-speed unit.

Four-wheel-drive hardware still needs a final adjustment

The front axle is a kingpin Dana 60 from a 1979 one-ton Chevrolet, fitted with Offroad Design brackets and G2 Axle & Gear manual locking hubs. It was part of the earlier four-wheel-drive conversion, before the Duramax, Allison and NP248 went in.

That drivetrain change moved the transfer-case drop, leaving the existing Dana 60 out of alignment with the new transfer case. Shaner plans to install a different Dana 60 that will line up with it. For now, the truck has no front driveshaft, an important qualification for a build described as a four-wheel-drive conversion: the system’s front axle is installed, but the current setup can’t send power to it.

At the rear, the original full-floating Corporate 14-bolt axle remains in place. Both axles use 4.10:1 gears. The combination preserves the truck’s heavy-duty rear hardware while matching the front gearing to it.

Lifted stance, familiar cabin

Skyjacker Softride leaf springs provide six inches of lift at the front. At the rear, two-inch Softride springs and two-inch lift blocks add four inches. Reaper custom traction bars help control rear axle movement, and Pro Comp shocks are fitted at all four corners.

The suspension clears 35×12.50R20 Fury Country Hunter M/T tires mounted on 11-inch-wide Detroit Steel Wheel Co. D-Town Smoothie wheels. Vintage GM hubcaps complete the look. The broad tires and lifted stance give the truck a conspicuously different footprint from a stock 1990 3500, while the steel wheels and hubcaps keep its styling tied to the era.

Shaner left the faded exterior as he found it. Inside, the original gauges and column shifter remain, with an Edge CTS monitor and a five-position switch for selecting engine tunes as the main modern additions.

The front seat carries its own history. It came from a 1990 Suburban 4×4 that Shaner’s family owned when he was young. They sold it in 2002 to buy a new Suburban, then bought the original vehicle back a few years later. Shaner remembers driving it as a teenager; now the seat has a place in the 3500.

A family tow rig, with a personal measure of success

Shaner built the truck to carry his family, tow a trailer and avoid the fuel consumption he associated with the original setup. He regularly pulls a 36-foot travel trailer and says the Chevy handles it “like it’s not even there.” He also says it tows better than his newer factory Duramax trucks, though no trailer weight, fuel economy or comparative test figures are provided.

Those claims are his experience with this particular truck, not a direct comparison across measured conditions. The build’s practical strengths are easier to identify: diesel power, a rebuilt Allison, 4.10 gears, heavy-duty axles and a large crew cab. The front-drive alignment remains unfinished, but the conversion shows how much of the project has come together around a drivetrain assembled from salvaged and family-sourced parts.

Shaner met the story’s photographer at the 2026 4-Wheel Jamboree Fall Nationals. Asked what matters most about the truck, he pointed to his four children enjoying rides in it. For a project built over years and through serious personal setbacks, that’s a more grounded measure of success than a dyno number—and the planned front axle swap is the next concrete step in making the truck’s four-wheel-drive hardware work as intended.