NASCAR Rumble (PlayStation)

GameShark, Pro Action Replay, Xploder, and Xplorer Codes

Note:
A GameShark or Pro Action Replay cartridge is required to use the codes featured below.

North American (NTSC) version

Unlock all difficulty settings:
300B7135 0002

Unlock locations, tracks, and legend drivers:
50000D02 0000
800B7136 0202
All codes above from nickliu.

Official codes from InterAct.
Codes from The Game Shark Code Creator's Club.