A/T problems, need help in worst kind of way
 

i recently got a 94 300z na with 67,000. the auto tranny is acting up bad.
first purchased it ran good, then in two weeks overdrive went out and 3rd get would slip out of gear when getting on it. last week only 1st and 2nd would work by manually shifting. now 1,2,d,od,n,r are in first gear i do believe since i can only do 40mph at 6k. park is neutral i believe. new to automatics for nissans. all fluid is good and red, no blown fuses, took inhibitor switch off and it seems to look normal.