The Dieselnaut is a large, tank-like vehicle used by the Dragon Hunters. It serves as a mobile fortress and base when the Dragon Hunters are hunting. Armed with harpoons and chains, along with a communication system and eighteen wheels, it is the main vehicle of the Hunters.
Though only tire tracks were shown, the Diseselnaut tows away the wreck of the Destiny's Bounty (and Kai, Jay, and Zane were likely transported in the prison cell following their capture), taking it back to Dead's End.
After the fight in The Pit, Kai, Jay, and Zane are loaded into the Dieselnaut's prison cell on orders from Iron Baron so that he can use them as bait to hunt Dragons. He then walks off, ordering Muzzle to ready the Dieselnaut and yelling at Arkade, Jet Jack, and Chew Toy. Cole and Wu then climb onto the turret at the top of the rig, only to be yelled at by Daddy No Legs, who was sent away by Wu. Iron Baron then declares the start of the hunt, and the Dieselnaut leaves Dead's End.
Later, the Dieselnaut is parked while the Dragon Hunters wait for a Dragon. When a Wind Dragon appears and tries to flee, Iron Baron orders pursuit of it. Cole gets on the turret and instead of hitting the Dragon, hits the stand where the ninja were held. He then gets off the Dieselnaut, only to find Daddy No Legs loading the ninja into it. The Dieselnaut then drives after the fleeing Wind Dragon. It fires a chain at the Dragon, which Heavy Metal runs across to land the Dragon. The Dragon is then loaded onto the Dieselnaut.
Jay wakes up and sees Daddy No Legs and Muzzle listening to a repeating broadcast from Lloyd from the communication device inside the Dieselnaut. The rig then arrives back at Dead's End. Young Dragon Hunters flock around it and the captive Wind Dragon and cheer.
The Dieselnaut arrives to find Daddy No Legs and Muzzle tied up.
On the hunt for the ninja and Faith, the Dieselnaut stops at the border of Oni land. Iron Baron then gives the order to cross the border and the Dieselnaut drives onwards. It then ambushes them outside a tunnel with other Hunter vehicles, speeders, and the HunterCopter. The ninja and Faith use two speeders and the Destiny's Wing to rush into the tunnel, where the Dieselnaut and the other ground vehicles follow. While most of the vehicles swerve to avoid rocks, the Dieselnaut just crushes them under its tracks. The Dieselnaut catches up to the trio of speeders used by the ninja, and Iron Baron leaps onto the Destiny's Wing. After the Wing is destroyed, the Dieselnaut follows the remaining two speeders out of the tunnel. Iron Baron then gets back onto the HunterCopter.
Faith then tells the ninja that to get away, they need to stop the Dieselnaut. Cole says that instead, they should take it. As the Rig comes in line with them again, they fire Chain Rifles at it, latching onto it. Wu then boards it, as Iron Baron expresses his fury about them trying to take his rig. Once onboard, Wu knocks Daddy No Legs and Muzzle off it. He then finds the drivers section and orders Arkade to get out. Arkade is then whisked away by Kai using a Chain Rifle. Wu then begins to drive the Dieselnaut as the other ninja and Faith board. Cole then gets on the turret again and uses it to destroy one of the Hunter Trucks. He then turns it on the HunterCopter and shoots it down, destroying it too. Iron Baron gets on another Hunter Truck and has his Hunters fire chains at the rear of the Dieselnaut. Faith runs to the back and begins to remove the chains, only to be chained by Jet Jack. She then grabs a screw as she is captured, separating the rig in half. The ninja the flee on the front half, while the back slows to a stop.
The ninja return on it to find Faith buried in the sand. When they go to free her, they are captured, and the front half is retaken and attached back to the rear part.
The Dieselnaut is parked up with the Dragon Hunters while the debate whether to free the ninja. It was presumably kept by them afterward.
- 87. "Radio Free Ninjago"
- 88. "How to Build a Dragon"
- 90. "Two Lies, One Truth"
- 91. "The Weakest Link"
- 92. "Saving Faith"
- 93. "Lessons for a Master"
- 98. "Endings"
- In early images, it was called the Diesel Utility Tank, and then The War Rig.
- Despite splitting in half in the show, the LEGO set is unable to do this.
- It was never actually seen in "Firstbourne," but the tracks Cole and Wu discovered were most likely that of the Dieselnaut.