car is in neutral when you push it, it tries to turnover

Ok this is an odd one. I just replaced the transmission on my 98 jetta 5 spd. I did not replace the clutch. Now here is the problem. after i replaced the trans it worked fine for a lil bit on my way home i stopped and the short plastic selector rod broke so i got a tow home, i replaced that and tried to take it for a test drive. but the battery was dead do i decided to push start it, it didn't work. I put the car into neutral and tried to push it back when i did this the car tried to turn over. any help would be great and if you have any questions pls feel free to ask

I heard before that sometimes push starting a car can be hard on it.. I don't know though that sounds strange? :runaround: