DETROIT — Owners of 2011-2019 model year Ford Mustangs are suing the automaker for what they allege are defective manual transmissions that have caused the pony cars to slip, jerk and clash gears while shifting.

A suit seeking class-action status, filed last year in California and transferred last month to U.S. District Court for the Eastern District of Michigan, alleges Ford knew about defects in the Getrag MT82 six-speed manual transmissions for a decade. Since 2011, the lawsuit says, Ford has issued seven special service messages and technical service bulletins related to shifting issues and other defects.

“The transmission is defective in its design, manufacturing, and or materials in that, among other problems, the transmission slips, jerks, clashes gears, and harshly engages; has premature internal wear, increased shift efforts, inability to drive, and eventually suffers a catastrophic failure,” the lawsuit says. “Ford repeatedly failed to disclose and actively concealed the defect from class members and the public and continues to market the class vehicles without disclosing the transmission defect.”

A Ford spokesperson said, “We typically do not comment on pending litigation.”

The automaker has faced legal issues for years surrounding its DPS6 manual transmissions used in Focus and Fiesta sedans. Last year it extended the warranty on certain 2014-16 model year Focus and Fiesta cars with dual-clutch transmissions by two years and 40,000 miles, and this year reached a new settlement in a class-action lawsuit affecting nearly 2 million customers.

Ford began using the Getrag MT82 transmission in the Mustang for the 2011 model year, when it replaced the Tremec T5 and TR-3650 manuals.

It began receiving complaints shortly after the MT82 transmission’s launch.

The lawsuit highlights a 2011 investigation into the MT82 transmissions by the National Highway Traffic Safety Administration. NHTSA found 364 complaints related to the gearbox but eventually closed the case after Ford took action to correct the problems, and it concluded there was “no unreasonable safety risk associated with the alleged defect.”

The plaintiffs include Brandon Lemons, who purchased a pre-owned 2014 Mustang GT in late 2018. He took the vehicle in for service in July 2019 complaining of a “grinding noise and a vibration through the shift knob.”

The problem has gone uncorrected.