When Brandon Shaner of Trafalgar, Indiana, bought this 1990 Chevy 3500 crew cab, it was a two-wheel-drive truck powered by a 454-cubic-inch gasoline V8 that barely ran. It leaked fuel, overheated, and needed plenty of attention. For Brandon, that made it a perfect project.
He had the immediate mechanical problems fixed within a day and drove the truck for about two months before converting it to four-wheel drive. But that was only the first major upgrade. Over time, Brandon began gathering the parts needed to replace the big-block with an LB7 Duramax diesel. The result is the truck you see here, a four-wheel-drive 3500 powered by a modified Duramax and backed by an Allison 1000 transmission.
Diesel Runs In The Family
Brandon works as a General Motors dealership technician, so he has accumulated knowledge that he was able to apply to this build. He is also very familiar with older Chevy trucks because he also owns a 1985 Chevy C10 and a 1985 Chevy K10. Duramax power is equally familiar. His family collectively owns more than 20 Duramax-powered vehicles and is heavily involved in competition sled pulling.
Brandon continued driving the 3500 while collecting components for the planned Duramax swap. Then the project was put on hold. “In 2020, I was diagnosed with non-Hodgkin lymphoma and underwent chemotherapy and radiation,” Brandon says. Thankfully, he reports that all is well today.
When Brandon was ready to resume work on the Chevy, he encountered another obstacle. Post-COVID prices had roughly doubled the cost of a Duramax drivetrain, so he found another route to diesel power.
Rebuilding An LB7 Duramax From The Ground Up
The solution came from Brandon’s brother-in-law in the form of a 2003 LB7 Duramax. However, it wasn’t exactly a ready-to-run engine. The Duramax arrived disassembled, with the engine components packed into two boxes and the remaining parts stacked on a skid. A broken valve spring had damaged the number one piston, but fortunately, the engine block survived.
Brandon rebuilt the Duramax and upgraded it with S&S Diesel Motorsport SAC45 injectors, which provide 45 percent more fuel volume. A Dan’s Diesel Performance Stage 2 64mm turbocharger handles boost, while a Wehrli Custom Fabrication 4-inch turbo horn provides 40 percent more airflow than the stock component.
Additional hardware includes Precision Fabrication Plus engine mounts and a Power Cool Manufacturing aluminum radiator equipped with dual SPAL electric fans. Ken Wolkens modified the 2003 Duramax wiring harness for its new application. Exhaust gases travel through a single 4-inch-diameter system, exiting through 6-inch tip. Most of the exhaust system was sourced from a former pulling truck owned by Brandon’s dad. Fuel is supplied from a 25-gallon tank through an AirDog 165-gallon-per-hour lift pump, while MTKB Racing handled the ECM tuning.
Allison 1000 And An NP248 Back The Duramax
Behind the LB7 is a 2003 Allison 1000 automatic transmission mounted to a custom crossmember. Brandon’s dad and brother are both Allison technicians, and they rebuilt the transmission for the project. Its upgrades include a Goerend Triple Disc Torque Converter.
From the Allison, power is routed through an NP248 two-speed transfer case sourced from a 2003 truck.
Dana 60 And Corporate 14-Bolt Axles
The front axle is a kingpin Dana 60 Brandon purchased through Facebook Marketplace. Originally installed under a 1979 1-ton Chevy, the axle uses Offroad Design brackets and G2 Gear & Axle manual locking hubs. The Dana 60 dates back to the truck’s original four-wheel-drive conversion, when the 3500 still used a different engine, transmission, and transfer case. Installing the Duramax drivetrain changed the transfer case drop, which left the existing Dana 60 out of alignment with the NP248. Brandon plans to install another Dana 60 that properly aligns with the transfer case. Until that change is made, the truck is running without a front driveshaft.
At the rear, Brandon retained the Chevy’s original full-float Corporate 14-bolt axle. Both axles are fitted with 4.10:1 gears.
Six Inches Of Lift And 35-Inch Tires
Skyjacker Softride leaf springs provide 6 inches of suspension lift at the front. At the rear, 2-inch Skyjacker Softride leaf springs combine with 2-inch lift blocks to produce 4 inches of total lift. Reaper custom traction bars help keep the rear axle planted, while Pro Comp shocks handle damping at all four corners.
The suspension provides clearance for 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 help maintain the truck’s old-school appearance.
Original Patina Meets Modern Diesel Tech
Brandon left the Chevy’s weathered exterior and aged patina intact. He took a similar approach inside, retaining things like the factory gauges and original column shifter.
The primary concessions to modern technology are an Edge CTS monitor and a five-position switch that allows Brandon to select the engine tune.
The front seat carries some family history. It came from a 1990 Chevy Suburban that Brandon’s family owned when he was young. The family sold the Suburban in 2002 to purchase a new one, then bought the 1990 back several years later. Brandon remembers driving the Suburban as a teenager, and its seat now has a permanent home in the Duramax-powered 3500.
Duramax Power With A Purpose
Brandon’s goal for the project was to create a truck that could carry his entire family and tow a trailer “without getting six miles per gallon.” The Duramax conversion has delivered exactly that. Brandon regularly uses the Chevy to tow a 36-foot travel trailer, which he says the truck handles “like it’s not even there.” He also says the Chevy pulls the trailer better than his newer factory Duramax trucks.
But the diesel conversion, towing capability, and fuel economy aren’t the only reasons the truck matters to him. At the 2026 4-Wheel Jamboree Fall Nationals Brandon told us, “The best thing about the truck is how much all four of my kids love and enjoy riding in it.”
Photos by Ken Brubaker and Brandon Shaner
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