quick question about tranny fluid

[hjalbert]

ok, my gmc has a 4 speed with granny low, guys at auto zone say it takes 80 wt gear oil, but they say 1 1/2 quarts, is this correct? another one, i cant find the plug on my rear diff, how do you check/add fluid? one more, any one know the cappacity for the transfer case? i usualy just put fluid in till it ocmes out the hole (do the same with the tranny, but i guess im wrong)