Volkswagen is recalling 640,309 cars in China through its Volkswagen Group China, Volkswagen Group Import Co, Shanghai Volkswagen and FAW-Volkswagen, as it was discovered that synthetic oil in the gearbox may cause electrical malfunctions in the gearbox power supply.

The car company said it will replace synthetic oil with mineral oil in the 7-speed double-clutch gearboxes (DQ200), but the announcement on the company's website did not mention the well-known Direct-Shift Gearbox (DSG).

Volkswagen has recalled a total of 1.23 million cars in China this year including its luxury brand Audi, topping all car manufacturers in the Chinese market. Of the recalled cars, 1.02 million involved cars were equipped with a DSG, according to Chinanews.com.

The latest recall is an effort to solve a problem different from the previous recall made earlier this year on April 2. It seems that the accumulated DSG problems require different solutions in China, after years of continuous complaints, Xinhuanews.com reported.

Earlier reports said Volkswagen Group China has confirmed that about 80,000 cars on the recall list were also recalled in April. As a result, these car owners need to return to the dealers again to fix their faulty DSGs.

However, new car owners' preference for Volkswagen is still strong enough to maintain a sales volume growth in the Chinese market, though the pace has slowed during the second half of the year. Volkswagen Group China is expecting a year-end sales volume of 3.2 million units.

Similar recalls have been made several times in the United States since 2009. Volkswagen of America is now offering a 6-speed automatic transmission together with a DSG for customers to choose, according to Securities Daily.