If the vehicle is moving when this happens, the detached driveshaft could cause damage the gearbox housing. A damage gearbox housing could leak gearbox oil onto the street and create a risk of a vehicle crash for both the driver and other motorists.
Volkswagen is recalling 25,594 MY 2006-2009 Jetta 5th generation equipped with 2.01 engine. The fastening screw contact surfaces on the driveshaft cover plate may not have been manufactured to factory specifications. Some screws may not have been torqued properly during assembly and could loosen over time, causing a knocking sound when the vehicle is in motion. The driveshaft screws could loosen to the point where the driveshaft detaches from the gearbox.