Factory manual page 3-13 "SAE80 API GL-4 Hypoid gear oil". Also see: http://www.lubrizol.com/DrivelineAdditives/AutomotiveGearOil/GL5.html for GL-4 vs GL-5.
OK, you are wrong. GL-4 (or gear oil rated for GL-4 and GL-5) should be used in the Raider. GL-5 should not be used because -- well. it's hard to believe -- GL-5 can actually cause premature wear of the kind of materials used in the gears. GL-5 will literally eat up softer metals like the brass syncros in a gearbox (I know the Raider doesn't have them, that's an example). Use- GL-5 at your own risk.
you know i gonna say amsoil, amsoil, amsoil. and when dd amsoil come out? 1972...mobil one? 1975