The car was constructed with aluminium panels over a tubular steel spaceframe, as was typical in F1 at the time, but featured a large number of new design features, the most interesting of which was the transverse-mounted gearbox – the T in the car's name stood for "Trasversale". The gearbox design allowed it to be positioned ahead of the rear axle, in order to give a low polar moment of inertia. The suspension was also significantly different from that of the 312B3, and the front of the chassis was much narrower. The handling of the car was found to be inherently neutral, not suffering from the persistent understeer which blighted the 312B3. Niki Lauda tested the car extensively during the off season, ready for a full-on championship challenge.