There's no simple fix for the Mega Mechanics and it's out with the old and in with the new. The installation of a new 10 million dollar jet engine in an A330 aircraft sees an intricate support and bracing technique used, while work on a 550 tonne excavator means 24 hours of preparation all comes down to an install that must happen within just seconds. It's dirty work changing the mud filter at the sugar mill and a coal handling vibro-gate causes trouble in Newcastle.

The Mega Mechanics go into high gear with a massive bucket wheel gearbox change. But a stubborn bolt and threatening weather may leave the 23 tonne gearbox swinging in the wind. A mysterious liquid on another gearbox at a coal mine has the Mega Mechanics turn detectives. Then the massive components of an underground longwall support and a dam radial gate have the cranes working overtime.

It's fifty Mega Mechanics versus five stories of mighty coal mining machines during a multimillion dollar maintenance shutdown. A 100 tonne crane is no match for mother nature and a dangerous lift is in jeopardy. A blown heat exchanger at a sugar mill needs a creative solution, sugar cane trucks and lining up and the crush needs to get back on track. All this plus a conveyor belt idler change and an A330 tyre install keep our Mega Mechanics moving.

The clock is ticking as the Mega Mechanics fight looming deadlines and technical challenges. A mighty metal bucket wheel is out of action at the largest coal export facility in the world, bulldozers are in pieces and their tracks torn apart in the mining hub of Mackay, and a 130-tonne train is sounding alarms on the jacking road in Brisbane. And the mine's breakdown crew are working hard across the site to keep the mega machines moving.

From rebuilds to repairs, massive machines are grounded as the Mega Mechanics are tearing them down and building them up. A landing gear pin has the team struggling to get a colossal A330 off the ground, and it's a mighty service on huge off-road trucks at the mine shop in Mackay. A Manitou won't move and blocking work at a multimillion dollar coal mine, while a monstrous bucket reclaimer needs some new teeth.

One of Australia's largest hydro power stations undertakes a high stakes valve replacement; they have six hours to get the 800kg replacement part down six stories.

The Kooragang Coal Terminal is buzzing with the arrival of a newly designed Ship Loading Spout and Trimmer Flap.

In Central Queensland, the army mechanics from the 2nd/14th Light Horse Regiment have two hours to overhaul a tank suspected of hoarding unwanted debris.

The mechanics at Brisbane's Gallipoli Barracks's Light Horse Regiment aim to complete two huge tasks.

The team at Murray 1, Snowy Hydro's second-largest power station, reassemble a massive power turbine after they find extensive cracking in the top cover.