You can test the crank sensor with a meter, It's a lot easier to look at a scanner but it can be done.

 

Just to add, they definitely did come with either an NV3500 or an NV4500 however the getrags will work in place of. However many say they have issues with the getrag, I don’t personally have experience so I can’t say. Just to keep to the subject though, it def seems like your issue is the crank position sensor. I had a very similar issue after rebuilding a 46RE and then installing it. Hit the sensor and couldn’t get it to stay running but it would turn over. Live and learn, I always remove them before taking the trans fully out and install carefully as I’m putting trans back in.