Johnson sourced the Cummins 3.9L 4BT turbocharged engine from a Case backhoe. Modifications are minimal and include a freer-flowing K&N air cleaner and custom 3-inch-diameter stainless steel exhaust. The powerplant is kept cool by a modified V-8-application Jeep radiator with dual Flex-a-lite electric fans. Amperage is produced by an Optima YellowTop battery that sits on a stainless steel battery tray. The engine rests on custom adapters that bolt to the factory motor mounts. Behind the engine is a salvage yard-sourced NV4500 four-speed manual transmission. Johnson says that during normal commuting the rig gets around 30 to 35 mpg.