Three years after its near collapse, US auto maker Chrysler has pulled back into market contention helped not just by snazzy new models but also a revolution on the factory floor.

Hundreds of small changes in production, more than any radical technology, has increased flexibility and output and brought once at-odds workers and management back on the same page, according to employees.

"You wouldn't believe this plant -- four years ago it looked like a dungeon. Now it's beautiful, clean," said Robert Figlioli, a tradesman at Chrysler's Jefferson North plant in Detroit.

Jefferson North is nothing like what it was before Chrysler tanked with the economy in 2007, eventually requiring a $13 billion government rescue that left it in the hands of Italy's Fiat after it came out of bankruptcy restructuring.

The specter of workers losing their jobs has also led to an acknowledgment of financial reality, with wages for new employees being half of what they would have been before the crisis.

But today, the plant hums with the feel of a high-tech firm: the aisles are clear and clean and the entrance has a giant poster with the four letters JEEP -- one of Chrysler's brands -- and the faces of hundreds of smiling employees.

"The environment is important -- to have a house that is clean with nice colors makes a difference," said Chrysler official Scott Tolmie.

"We want that Apple store look -- it makes people want to work here."

Scott is one of those responsible for Chrysler's WCM Academy -- for World Class Manufacturing -- that was launched in January to implement Fiat's three-year-old approach to modern car-making.

It is inspired by Toyota's renowned hyper-efficient "just in time" production method, which aims to maximize efficiencies of parts supply and delivery and capitalize on employee input to keep costs lower and quality high.

Posters shouting 'I am WCM' decorate the pillars around the factory, which turns out the popular Jeep Grand Cherokee and the Dodge Durango SUVs.

For workers, WCM means new tasks, like keeping their work stations clean and machinery painted in like-new condition.

"It actually helps the operator -- you're working with pride. In the long run the pride is going to show," said Figlioli who is the vice president of the United Auto Workers union local and has worked at Chrysler for two decades.

It represents a broader change in the working environment, he said.

People are coming to work with better attitudes: they have more say on the job, there is more focus on workplace safety. In return, management is more willing to listen to and implement worker ideas, said Figlioli.

WCM, which Fiat says has saved the group hundreds of millions of dollars over the first half of the year, is not about technology and automation. The role of workers is the focus.

The academy trains them to use equipment and studies how they work to boost efficiency in movement.

"In the 1980s the trend was to have unmanned factories. That didn't work," said Chrysler spokesman Gualberto Ranieri.

The revival and changes have meant sacrifices for the workforce, however -- new workers earn half the wages of pre-crisis levels, but Figlioli says it has been necessary.

"The majority of the personnel has accepted this change," he said.

"We were coming out of a bankruptcy. If we wanted our job, we had to make a change. The people in this plant know that if they don't perform, their plant can close."