While Paused: L2, Square, R1, Circle, R1, L1, Circle, L2, Square, R2, Square, R1.
Pause, then press L1,L2,R1,R2,L1,R1. Go to the Time Attack mode and look at Class 3 Fords. The trucks aren't available in career mode.
While Paused: L1,L2,R1,R2,Circle,Circle
While paused: L1,L2,R1,R2,Square,Circle.
While Paused: L1,L2,R1,R2,Square,Square