20 years since the first 4-wheel-drive Golf

- 1986: the Golf syncro brings four-wheel drive to the compact class
- Volkswagens with four-wheel drive: Golf, Passat, Sharan, Multivan, Touareg, Phaeton
- Stress-free winter motoring: Volkswagen's 4MOTION four-wheel drive offers extra safety
WOLFSBURG, Germany - Despite a still hesitant start, winter is here. This means of course we can brace ourselves for those strenuous drives at sub-zero temperatures. Faced with ice, snow and generally unpredictable road conditions, a growing number of motorists would like four-wheel drive. However, by no means do all carmakers offer four-wheel drive in their high-volume models. Not so at Volkswagen, where four-wheel drive has now been available in the Golf for 20 years. Besides this current example, Volkswagen also supplies four-wheel drive (4MOTION) in the Passat, Sharan, Touareg and Phaeton, plus the Multivan, Caravelle and Transporter.

syncro in the Golf

Taking a brief look back, the first four-wheel-drive version of the Golf came out in 1986. As it had so often done before, Volkswagen made a new technology available to a wider public. The Golf syncro gave many motorists their first opportunity to own an affordable car with optimum traction even under difficult road conditions.

syncro in the Passat and Transporter

The four-wheel-drive Passat Estate GT syncro had already been launched two years before. The system's central differential compensated for wheel speed differences between the front and rear axles when cornering. On slippery ground the differential could be locked to ensure optimum traction at both axles.

However, this was also the most costly form of four-wheel drive system; to build a Golf syncro at a marketable price, a different engineering solution would have to be found. Fortunately, Volkswagen had developed a technology for the four-wheel-drive Transporter, launched in 1985, which suited the Golf perfectly: the viscous coupling. It connected the Golf's substantially unmodified front-wheel drive with the differential of the syncro rear axle and worked fully automatically without the need for any intervention by the driver. The silicon liquid in the viscous coupling allowed the front and rear axles to turn at different speeds when passing through bends. And when necessary, for instance if the front wheels were standing on sheer ice, it transmitted virtually 100 percent of the engine power to the rear axle.

The same engineering principle was later adopted for the front-engine Transporter T4 and the third-generation Golf. The career of the viscous coupling continued until the introduction of extremely fast reacting electronic vehicle dynamics control systems, such as ESP in the Golf IV; at the same time, the name syncro disappeared from the vehicle ID plates.

4MOTION for the Golf, Passat, Sharan and Multivan

Syncro made way for a new system with a new name: 4MOTION. The Golf Europe's most successful compact car shares this technology with the Passat, Sharan plus the Multivan and its close technical relatives, the Caravelle and Transporter.

In all of these models an electronically controlled Haldex coupling makes the connection between the front-wheel drive and the rear axle. Its core elements are a multi-plate clutch and an annular piston oil pump. At the slightest difference between the speeds of rotation of the driven front axle and the rear axle, the oil pump produces pressure, closing the multi-plate clutch and the rear wheels instantly receive power. At the same time, the ESP's control electronics monitor the Haldex coupling. When there are signs that the vehicle is losing directional stability, ESP opens a control valve between the oil pump and the multi-plate clutch, thus interrupting the connection between front and rear axles. ESP can then brake each wheel independently of the others to prevent the vehicle from breaking away.

Source: media.vw.com