Torque converter issue?

Hey there everyone. Been tackling a pretty tough issue here for a long time. I have a 73 dart sport, original 340 car. Now has a 1971 360 in it. I have been battling a weird issue to where the car would only start if the door was open. I somewhat fixed that, but now driving it is a complicated issue.

This is what happens:

the car starts, runs and idles just fine, but when you go to change gears(automatic) it wants to stall, and starts running very poorly. The linkage seems to be off because when the car is in park, the orange indicate show it about halfway to wear it should be( park is not lined up with park on the steering column. I don’t know if this could contribute to the problem, or if it has to do with tranny, and or torque converter. Or maybe the neutral safety switch is bad and sending mixed signals on what gear it should be in and when. Another interesting thing to note, is that the car can be started in practically any gear. Also, sometimes when I got it to drive, it would stall while driving, but not because of the engine. Also it would sometimes lerch into gear when stopped.

I would greatly appreciate any help, thanks