So my dad and I have been working on my brothers Lincoln ls 3.9 v8 2000. Problem we are having is the automatic transmission won’t go. It goes into gear but no movement. Just creeps forward. Now when the slap shift is engaged it works. Now we’ve replaced selenoid pack. No metal in the trans at all replaces fluids etc. my dad is a mechanic so everything that can be done he can do. We’ve searched and searched forums etc and people have mentioned shifter diodes or replacement etc but we took the shifter out reached down and could switch the gears with the cable manually so it’s doing the same thing with out shifter hooked up. We are stumped. Anyone have any suggestions ? We can’t even find diagrams of the trans or shifter in this car.