Vibration issues

I was finally able to change the tail shaft bushing and bearing. I still have a vibration though it seems to not be as bad as what it what before. While I had the tail housing off I did grab the tail shift and it has some movement in it up and down not a lot but I do not know if that's because if the housing being off or dose that mean an issue with the transmission internally?

I am planning on running the car with out the rear wheels. Checking my axles incase they are not straight. I may go back to the old wheels I had in when I got the car just to rule out everything but the transmission.

I had my girlfriend ride in the back seat of the car and the vibration seems to only be felt in the center if the car. Can place your had on the trans tunnel and feel the vibration there.