THE fundamentals are absolutely small-car orthodox, with a five-speed manual transmission standard and four-speed electronically-controlled automatic. But the Cruze has the added twist of an all-wheel drive system. The powertrain has a power takeoff using a spiral bevel gear drive unit to transfer power via a propellor shaft to the rear. At the central under-floor location the prop shaft incorporates a viscous coupling which functions only when there is a differential in speed between the front and rear sections of the prop shaft. A rear differential and driveshafts complete the AWD package. In normal situations the Cruze is a front-wheel drive, just like any small hatch, but when the viscous coupling detects front wheel slippage via that speed differential between the front and rear sections of the propellor shaft, then it transfers drive to the rear.