The first and second generations, produced from 1979 to 1984 and from 1984 to 1992 respectively, shared transmissions with Volkswagen’s engine options for the Jetta. These Volkswagen Jetta transmissions for the Jetta types A1 and A2 were mated to different gasoline and diesel engines being offered then by Volkswagen. All the engines for the Jetta during these period were 4-cylinder engines and were mated to 4- or 5-speed manuals or 3-speed automatic transmissions. The 5-speed transmissions in particular were close-ratio units adapted from the Volkswagen GTI.
With the third generation Jetta, only a 5-speed manual and a 4-speed automatic were made available. The third generation Jetta, the type A3, was made from 1992-1999.
In 1998, production was begun in Europe for the type A4 Jetta for which this variant was marketed until 2002. For the Chinese and Mexican markets, however, 1999 was the year production began, which continues up to the present. For this variant, 11 gasoline engines and 7 diesel engines were available, depending on market and trim level. These powerplants were mated to one of 4 available Volkswagen Jetta transmissions, namely a 5-speed manual, a 6-speed manual, a 5-speed automatic or a new 4-speed 01M automatic.
The 01M transmission is an in-house development by Volkswagen, and is basically a hydraulic four-speed automatic transmission. It is controlled by a transmission computer located, in the case of the Jetta, in the backseat. Over time, it was discovered that increased resistance (due to age) in the wires caused wrong readings from the speed sensors, which tricked the transmission computer into defaulting into fail-safe mode. When this happened, the transmission would be locked into second gear and the dash indicator lights for the transmission would all light up simultaneously. The 01M transmission was replaced in later Jetta models by a 5-speed automatic designed by a Japanese company, Aisin.
2005 saw the debut of the 5th generation Jetta and with it, a new transmission design dubbed the DSG. This Jetta generation has 11 gasoline engine options and 4 diesel ones. The transmissions available are a 5-speed manual, a 6-speed manual, a 6-speed automatic, 6-speed DSG and a 7-speed DSG.
The DSG transmission introduced for this generation is derived from the Porsche 962 competition cars from the 1980s. Originally a Borg-Warner design, it was licensed for use to the Volkswagen group, which meant that it, and various improved models, could be used in Volkswagens, Porsches, Audi, Seat, etc. The DSG is a manual transmission design with uses dual clutches, is electronically controlled and has no need for a clutch pedal. It offers up to 15% better fuel efficiency and extremely fast shifting. On the other hand, it is more expensive to manufacture, inherently more complex and needs special lubricants to work properly.
The sixth-generation Volkswagen Jetta transmissions will likely be carryovers from the previous generation. In 2012, a hybrid Jetta is expected to be introduced to North America, where interest in hybrids and alternative-fuel vehicles continues to rise.