We were checking the compression in the car and tried to turn the engine over by hand and it wouldn't move. Now the engine is out of the car, heads are off and the trany is off. All of a sudden we can turn the engine over by hand.Could the problem be the transmission? The engine wasn't making any noises before we took it out. But it seemed to have a hard time turning over.Compression was great also. We thought it might be the main bearings but now that it,s turning I'm thinking the trany.When I drove it a few weeks before i seemed to get a lack of power i couldn't get the engine over 50kmh. the engine is a 351c 4v and the trany is a c6. Should I be able to turn over the trany by hand once its out of the car?