The drive is transmitted from the gearbox drive flanges through the drive shaft by means of inner and outer CV joints. The outer CV joints include alignment shafts that connect to the front wheel hubs.
Until April 1988, the shafts were attached to the hubs with nuts, but later models use bolts. The inner and outer joints can be replaced separately.
[The original version of the article is posted on the website: AudiManual]