Over the years, we've seen cars reach the million-mile club. It's the best testament to vehicle durability and coincidentally, a number of those vehicles we've covered were Toyotas.

Specifically, two Toyota Tundra units from 2007 have reached the seven-digit mark. One of them was owned by Victor Sheppard, which reached one million miles (1,609,000 kilometers) in 2016. Toyota gave Sheppard a brand new Tundra to replace his old truck.

The automaker then studied the vehicle to see what held up in its nine years on the road. And today, Toyota Chief Engineer Mike Sweers shared what he and his team learned and applied to the 2022 model.

Gallery: Toyota trades new Tundra for one with a million miles

When Toyota received Sheppard's million-mile Tundra, the only things that weren't working were the sun visor detent on the driver’s side and the odometer that reached its 999,999-mile limit. Even the frame of the seat was intact and the foam was unworn, showing only light wear and tear.

However, the truck's bed showed severe stress, which prompted Sweers to build a more durable bed for the 2022 Tundra. He used a lighter, sturdier, and less corrodible composite material, which was tested by throwing rocks, cinder blocks, and even a V8 engine on it. The bed survived without a dent.

Meanwhile, Sweers went for a linear, ladder-shaped frame for the Tundra instead of the usual one from the predecessors. The new design gives wider support to the bed, allowing for a more even distribution of weight. He also focused on storage inside the truck, including the one found under the rear seats.

For the oily bits, Sweers used a wider 1 3/4-inch drive chain – one-quarter wider than all previous Tundra models.

"When you increase the width of the chain, your planetary gear, your shafts, everything else has to be beefed up to go along with that," he added.

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