Just asking why would it have forward gears when it was on the lift? Granted netural acted like it was in gear and it only made one gear change from second to 3rd
Because there is a fairly serious misdirection of fluid somewhere.
It could easily drag clutches and drive the wheels when they are off the ground, and fluid going someplace it doesn't belong when in neutral.
Basically what you have is a trans that slips so bad it won't drive the wheels with the cars weight on them.
Could be loose VB bolts, a cut lip seal, broken sealing rings, or half a dozen other things that only an air check or tear down and inspection is going to tell.
If it makes you feel any better, it should be pretty obvious when it's found.
Just don't burn it up messing with it, because it's not something that it's going to suddenly quit doing.
