I need help

[Scrappy]

OK I just bought an 86 prelude 2.0si automatic i bought it with tansmission problems (it don't move) when you put it in D4 it dont move and with out pushing the button on the shifter you can puch it into reverse when you put it in D3 same but it slowly slips out of gear in between D4 and D3 then if you put it all the ways down into 2 then you have to hold it there really hard if not it pushs up into D3 and slowly back up to D4 So I guess what i'm asking is if there is just somthing wrong with it or if i need i whole new transmission?
Thanx