(CBS) Two of the most popular vehicles on the road could be dangerous, and now the government wants many of them recalled, reports CBS News Correspondent Mika Brzezinski.

Six hundred thousand popular vehicles could be recalled if DaimlerChrysler complies with the government's demand.

The recall order covers model years 2000 to 2003 of the 4x4 Dodge Durangos and the Dakota pick-up trucks with four-wheel drive.

The government action highlights a problem first uncovered by CBS News more than a year ago.

"Unfortunately, it could have been a really deadly situation," Monique Conrad, a former Dodge Durango owner, told Brzezinski

Back then, Monique Conrad's 2000 Durango had only 31,000 miles on it when the right front wheel suddenly flew off while she was driving.

"My tire, along with a piece of metal about a foot long, was bouncing across this four-lane road," Conrad said.

Her experience along with similar complaints prompted the government to investigate possible premature wear of Dodge Durango upper ball joints — a ball and socket attaching the wheel assembly the vehicle.

Since our first report, CBS News received hundreds of e-mails, photos and calls from viewers around the country like Kate McGeehan-Sawyer from Maine.

"The wheel just flew out," McGeehan-Sawyer said.

Tina Czech, from Massachusetts, experienced a similar road trauma: "The wheel had completely fallen off," she said.

And Joyce and John Gosch, truck owners from Pennsylvania, pointed to the damage: "This just ripped off," John Gosch said.

As the complaints piled up, the government expanded its investigation to include the Dodge Dakota pick-up truck, which uses the same upper ball joints. Dakota owner John Cohron, said his truck looked the same as many others with similar tire trouble, after his wheel flew off.

"So you got out of your truck and what did you see?" Cohron said. "I saw the tire and the wheel underneath the front end of the truck."

According the government, a third of the nearly 2 million vehicles investigated had defective upper ball joints. And almost all were produced at an Indiana plant. Customers paid up to $1,200 dollars to replace these parts — a recall could mean a huge financial hit for DaimlerChrysler.

"The cost is certainly going to run into hundreds of millions of dollars," said Clarence Ditlow, from the Center for Auto Safety.

DaimlerChrysler also faces mounting lawsuits like the one filed by David and Christina Shaffer. They were on the highway in their Durango with their four young children when suddenly they experienced a shock of their life.

"It seemed like we went into a frenzy of flipping," David Shaffer said.

Bodies went flying everywhere. Christina — who was pregnant at the time — suffered numerous injuries including a broken neck. Doctors were not optimistic.

About the baby, David Shaffer said, "there was no certainty. You know they actually came to me and recommended to me to take the baby's life."

Medical bills forced the family into bankruptcy. And while they consider their new baby girl a miracle, the Shaffers say they wish DaimlerChrysler had acted sooner.

"It could have been our whole family gone," Christina Shaffer said.

In a statement issued late Thursday, DaimlerChrysler maintained that the upper ball joints do not pose a safety concern and that owners have substantial warning of any problems — like noise or tire wear that would be picked up during routine inspections.

The company says it is reviewing the governments order for a recall and will respond next Monday.