what to use??????????

[onetonwrecker]

hey guys i bought a 64 gmc 3/4 with a 305 v6 real cool truck i got it for a old lady it was her husbands truck who died a few year before this the truck had been sitting for sometime i brought it home and got it running now i want to change some other fuilds like rear diff and trans its got a dana 60 rear what should i use for fuild? Do i need to add an additive? and also has a 4 speed trans what should i put in that? thanks guys