Transmission problem

The transmission in the car did not work I thought. so, I swapped it with a different one which was working in the other car the day before I swapped it. Now when I go to start the car and try moving it I get no gears at all. I mean it goes into gear without even pushing the clutch in, but it acts like there's nothing. I can spin both tires front tires either way backwards or forward when it's in gear. should not be able to do that, I don't think. So, I got the transmission out of the car, and I grabbed the output shaft and turned it and stuck my finger inside where the CV goes to see if the gears in there turn. They do turn unless I put pressure on it with my finger then they don't turn. I was wondering if they were supposed to because I got no movement on my car.