You can turn the engine over in park and neutral easily. Think about it; the engine is running (turning) while the tranny is in these positions.

As for how the vehicle is locked, take a look at howstuffworks.com They have all kinds of great stuff there. Here is the article on how an automatic transmission works: http://auto.howstuffworks.com/automatic-transmission.htm

[color:"darkgreen"]1986 4Runner - 4" IFS - 63" Chevys - 33" ATs - 5.29s - Rear Detroit
Sliders - Kayline - Rebuilt 22RE - On Board Air AND Factory AC
www.xtremefabricator.com[/color]