Auto safety regulators have opened preliminary investigations into new Ford Motor Co Mustangs with manual transmissions for possible shifting problems and diesel Volkswagen Jetta sedans for possible fuel leaks.

Spokesmen for both automakers said they were not aware of any accidents or injuries related to the issues and were cooperating with the National Highway Traffic Safety Administration in its preliminary evaluations.

A preliminary investigation is the first step in a process that could lead to a recall if regulators determine that a manufacturer needs to address a safety issue.

The NHTSA said on its website that it had opened a preliminary investigation into an estimated 26,000 Ford Mustangs from model years 2011-2012 over potential problems with erratic shifting almost causing collisions due to a temporary loss of power to move.

The safety agency said it had received 32 consumer complaints claiming an inability to shift into gear on the manual transmission-equipped cars. Some of the complaints alleged incidents occurred while merging into high-speed traffic, and others while turning left across oncoming traffic.

The NHTSA also opened a preliminary probe into an estimated 40,000 Jetta TDI cars from model year 2011 after receiving seven complaints claiming leaking from the fuel line to the No. 2 fuel injector on the vehicle.

(Reporting by Ben Klayman; Editing by Lisa Von Ahn)