Trans doesn't go in gear. Now what?! Please Help

It'll go in gear with the kickdown unhooked. Just don't want to run it that way. If replacing the converter is all you did my guess is it's either a bad converter like A/J mentioned or you didn't get the pump gears aligned correctly and snapped them off when you bolted the trans up. An easy test to see if the converter is aligned to the front pump is to unhook one of the trans cooler lines and fire it up and put it in gear and it should pump fluid out. If it does that it sounds like a bad converter, or possibly one made for the wrong input spline count as 66 and earlier used a 18 spline input shaft