IN automatic transmission Subarus - the Forester GT tested was an automatic - the all-wheel drive is a computer-controlled electronic system that regulates drive to all four wheels through a multi-plate transfer clutch. The active torque-split system works in conjunction with the automatic transmission to monitor speed, gear selection, throttle position and wheel rotation information and vary drive to the front and rear wheels accordingly. The manual GT uses a different system with a viscous limited-slip centre differential. In normal conditions this system operates with a 50/50 torque split between the front and rear axles, but the viscous LSD automatically adjusts the torque distribution under unstable driving conditions such as on slippery surfaces or during hard acceleration. The Forester GT also uses a limited slip differential (LSD) on the rear axle to enable the transfer of power between the rear wheels depending on available traction.