An automatic transmission designed to save fuel has increased complaints among Ford customers who claim it's not a smooth operator.
More than 60,000 Ford cars in Australia may be the subject of a new class action because of a transmission that lawyers claim is "unsafe to drive".
Ford's twin-clutch automatic -- a similar design to those used in Volkswagens -- is fitted to its Fiesta hatchback, Focus small car and Ecosport SUV.
According to Bannister Law, which is proposing the Class Action, the transmission is "defective" because it "slips, bucks, jerks, and harshly engages when driven".
The proposed action only includes Fiesta, Focus and Ecosport models made from 2011 to 2014, even though two of the three cars on sale today continue with the same transmission.
Ford replaced the transmission in the Focus to a regular automatic with an update introduced last year.
These faults constitute major defects and trigger a full refund under Australian Consumer Law
"Customers who've contacted us believe there is clearly a problem with this particular gearbox, some people have returned to dealerships to get their cars fixed up to 10 times for repair or replacement, while others are being asked to sign confidentiality agreements in order to get a refund," said Charles Bannister, the principal of Bannister Law.
"We believe these faults constitute major defects and trigger a full refund under Australian Consumer Law."
On a website inviting owners of affected vehicle to register their interest, a statement from Bannister Law says: "some consumers are concerned that, as a result of their experiences on the road, their vehicles are unsafe to drive".
The law firm says it will start the Class Action "should Ford not agree to compensate customers appropriately".
A statement from Ford Australia said: "Ford is committed to providing its customers with top quality vehicles. We are equally committed to addressing potential issues and responding quickly for our customers".
The car maker said it has "addressed the majority of our customers' questions and are pleased with our ongoing improvement in customer satisfaction levels".
A Ford representative said Ford's "PowerShift" transmission uses an "advanced configuration that provides exceptional powertrain efficiency, along with the potential for unique shift feel compared with conventional automatics".