The technology is available in more than 100 model versions, ranging from the A4 to the R8.

Audi is celebrating a milestone as its eight millionth Quattro-equipped vehicle rolls off the assembly line.

The all-wheel drive system is now 37 years old, debuting with the Audi Quattro coupe in 1980. Putting power to all four wheels allowed the Ur-Quattro to dominate rally racing for several years.

Audi claims its modernized Quattro drivetrains are now available in more than 100 model variations. It comes standard on the Q7, A4 Allroad, A6 Allroad, A8, R8 and all S and RS models, and is an available option for all other models in the company's lineup.

"In 2015, 44 percent of all Audi customers worldwide chose models equipped with Quattro drive," Audi notes. "The Audi Q5 topped the list with about 262,000 units."

Five different Quattro drive systems are currently in production. Compact models with transverse engines use an electronically controlled hydraulic multi-plate clutch at the rear axle, while the R8 employs a front-axle clutch. Longitudinally mounted engines are typically paired with a self-locking center differential and a 40:60 torque split.

A more advanced system is used for Audi's most powerful engines, adding multiple clutches to distribute torque between the rear wheels. Putting nearly all torque to one wheel can help push a car through a corner while minimizing understeer.

The latest advancement centers around efficiency. Vehicles outfitted with an 'Ultra' Quattro system can decouple the rear axle to reduce drag.

The eight-millionth Quattro car was produced at Audi's new production facility in San Jose Chiapa, Mexico. It was a garnet red Q5 2.0 TFSI Quattro. The company did not disclose a destination country for the milestone vehicle.