Transport Canada is investigating a "significant" number of concerns over Ford Focus and Fiesta models after owners reported their cars acted erratically, in some cases jerking forward or stopping suddenly.

The federal department opened what it calls a "defect investigation" in February 2016. As of Oct. 20, it had received complaints from 128 Canadians about the transmission in some 2011-2016 Ford Fiesta and 2012-2016 Ford Focus vehicles.

One of those complainants is Jordan Bonaparte, a Halifax man who bought a new Focus in early 2013 as he and his wife awaited the birth of their son.

"I don't think it's safe to be on the road," he said.

'The car would jerk forward'

Bonaparte wanted a vehicle that was safe, reliable and worry-free. The Focus was sold as an automatic, so the couple had no idea it was run by a manual transmission that shifted automatically with the help of a computer. That means the driver has a traditional automatic shifter with park, reverse, neutral and drive options, while the computer does the work of operating the clutch and shifting gears.

Bonaparte said, about a month after the purchase, the car started rumbling when he accelerated.

"It would go from bumping to, all of a sudden, the car would jerk forward five or seven feet," he said. "The biggest issue at first was my fear of hitting the car in front of me or slowing down and having the car behind me hit me."

When stopped on an incline, the car would also roll backward as Bonaparte tried to move forward.

3 replacements

The Ford dealership gave him differing reasons for the problem, he said.

"It had to do with multiple drivers of the car [or] it was normal operation of the transmission," Bonaparte said.

Jordan Bonaparte was provided with this replacement vehicle while he awaited the third transmission replacement in his 2013 Ford Focus. (Yvonne Colbert/CBC)

With approximately 45,000 kilometres on the vehicle, Bonaparte was waiting for his third transmission or clutch replacement when he spoke to CBC News earlier this month.

He said the prior two replacements gave him about a month of fairly smooth driving until the problem started again.

The problems were so bad after the last replacement that he and his wife stopped driving their three-year-old son in it.

'They fear for their safety'

Bonaparte and his wife aren't alone. Toronto lawyer Ted Charney says he is preparing a national class action lawsuit against Ford over what he calls a "transmission defect."

Charney said his firm has been contacted by 1,000 Canadians, some of whom he says have had their transmission replaced as many as seven times.

"All of the calls are pretty much the same," Charney said. "They fear for their safety, they don't want their family in these cars."

Charney, who estimates there are 150,000 affected vehicles in Canada, said there are also class action lawsuits underway in the U.S. and Australia.

Lawyer not aware of injuries or fatalities

He's not aware of injuries or fatalities because of the problem, but has received "a number of complaints from people who have been in accidents which they attribute to the defects in this vehicle, because the vehicle lurches forward or it doesn't proceed forward when they step on the pedal to accelerate or it suddenly stops."

"Many of them have been in situations where they have almost had an accident," he said.

Like some of Charney's clients, Ford offered Bonaparte a discount on the purchase of a new vehicle. Charney said that's not enough.

"What people have to decide now is whether to park the car or get rid of it at a very low price or just keep driving it and taking their chances. I mean, it's a very difficult situation."

'It's only a matter of time'

Bonaparte said he's been asking for a rental for three years but only got one recently as he waited for his third transmission replacement.

"Only after speaking to you — and letting Ford know that I was speaking with you — did they agree to offer me a rental car, something that I'd been asking for since the first transmission was replaced," he told CBC News.

He thinks Ford should recall the vehicles.

"It's only a matter of time before someone's killed," Bonaparte said.

Company says it's discussing solutions

​Ford Canada said it takes customer concerns seriously and is "committed to investigating those concerns and responding to our customers." Spokeswoman Michelle Lee-Gracey said in an email that the company continues to discuss solutions with Bonaparte.

Transport Canada says anyone with a concern about vehicle safety should report it to them.

It's in the process of separating driveability and service-related issues on the Ford models from those that are safety-related, such as loss of propulsion, according to an email from a Transport Canada spokeswoman.