Unlock 1983 Grave Digger:
Beat one season of cash grab on normal difficulty.
Unlock Champ Trucks:
Beat one season on any difficulty level with any truck.
Unlock 20th Anniversary Grave Digger:
Beat the 2nd season of cash grab on normal.
Unlock The Incredible Hulk:
Beat the 3rd season of cash grab on normal.
Unlock The Dog Pound:
Finish any first season on extreme with a champ truck.
Unlock Big Yellow:
Play through any type of second season on hard with a champ truck.
Unlock The Hooch:
Play through the third season of any type on hard.
Unlock Inland Truck:
Finish any season on hard with a champ truck.