The Fiat 128's arrangement had numerous differences. As engineered by Dante Giacosa, it featured a transverse-mounted engine with unequal-length drive shafts and an innovative clutch release mechanism — an arrangement which Fiat had strategically tested on a previous production model for a full five years, the Primula from its less market-critical subsidiary, Autobianchi. The layout enabled the engine and gearbox to be located side by side without sharing lubricating fluid while orienting an electrically controlled cooling fan toward fresh air flow. By using the Primula as a test-bed, Fiat was able to sufficiently resolve the layout's disadvantages, including uneven side-to-side power transmission, uneven tire wear and potential torque steer, the tendency for the power of the engine alone to steer the car under heavy acceleration.