Italian luxury sports car manufacturer Maserati used the North American International Auto Show to highlight the addition of a new, 6-speed hydraulic automatic transmission to its Quattroporte.

"The Maserati Quattroporte with fully automatic gearbox is a fundamental innovation for us," said Roberto Ronchi, chief executive officer and general manager of Maserati S.p.a.

He noted the company didn't want to tamper with the Pininfarina design of the car or make big changes, because the vehicle has been successful with total sales worldwide of 9,000. All of the sales so far have been with Maserati's DuoSelect manual gearbox, which continues to be offered.

German transmission builder ZF developed the new transmission with Maserati to provide fluid, seamless shifting. Maserati said it was particularly important that the car's V8 engine power comes on strongly at low speeds and without limits.

The Quattroporte has a 400-horsepower 4.2-litre double overhead cam V8. Peak torque is 339 lb-ft with the new automatic transmission and 332 lb-ft with the DuoSelect.

Maserati said the addition of the automatic should help Quattroporte sales in the U.S., "where customers are used to long journeys and are particularly attentive to driving comfort." The new 6-speed automatic also is available in the Quattroporte Executive GT and the Sport GT models.