Complaints about the transmissions in Ford's Focus and Fiesta models are nothing new, but an investigation by the Detroit Free Press suggests the car maker knew about the issues and decided to sell the cars anyway.
The issue involves cars from the 2011 to 2016 model years.
Drivers complain that the car is slow to get into gear, that it will randomly lose power while driving, or that it will jolt forward from a stop.
The paper suggests that Ford engineers noticed the problem during testing.
It cites an internal email from product development engineer Tom Langeland, which notes a "nasty launch judder."
It goes on to say, "We also cannot achieve a driveable calibration that will get us to production. The clutch torque delivery MUST BE IMPROVED"
The Free Press looked at thousands of consumer complaints and found 50 unreported injuries, but no deaths.
Ford insists that the vehicles are safe to drive, suggesting that if the cars slip out of gear, drivers still have steering and brakes and are able to coast to the side of the road.