Imagine a fire truck roaming the streets, but instead of responding to fire alarms, it hauls machines instead.

This is the wild project currently underway at Grind Hard Plumbing Co., where the team is turning a massive 1965 American LaFrance fire truck into a one-of-a-kind toy hauler, powered by a Cummins engine they pulled from a school bus.

In their latest video, the team tackled every important step to get the Cummins swapped fire truck moving under its own power for the first time.

The Driveshaft Puzzle

The biggest challenge was creating a custom driveshaft to connect the school bus transmission to the fire truck’s rear axle. After discovering that the splines from the two different drivelines didn’t match, the team had to get creative.

They machined a custom steel sleeve on a lathe to join the two mismatched shaft sections. Lacking a press large enough for the job, they resorted to what Ethan Schlussler called an “incredibly sketchy” method.

He then used a hydraulic bottle jack positioned vertically under one of the shop’s main support beams to press the pieces together. Despite the unorthodox approach, the final result was a success. “Wow, that was severely lucky,” Ethan said, “it’s within, like I would say, half a degree.”

First Fire-Up and a “Mad Max” Drive

With the driveshaft built, the team mounted a radiator using repurposed BMW transmission mounts and fabricated custom brackets. After setting up a temporary fuel can and hooking up multiple jumper packs, they successfully fired up the Cummins swapped fire truck in its new home.

“Look at that! It runs, it moves forward, the radiator isn’t fully attached,” Ethan exclaimed. The first test drive was performed in true grind hard fashion, with one person steering and another sitting in the open engine bay operating the throttle directly by hand.

Ethan joked it was a “Bluetooth throttle,” and described the scene as “one of the more Mad Max things we’ve done in a minute.”

Unique Cummins Swapped Fire Truck

The successful first drive was a major milestone for the project. As Ethan celebrated, he said, “There would be no more having to push it in and out of the shop.”

It’s not every day you see a vintage 1965 fire truck get a new life, especially one that involves a Cummins engine swap and a conversion into a heavy hauler for other crazy machines.

This project is a perfect example of the wild ideas and creative fabrication that the Grind Hard Plumbing Co. team is known for.