My shop teacher has a turbo (forget what kind.. ill post it tommorow) and if you spin it as fast as I can, it freewheels for about a sec than stops. Also, there is about a mm of shaft play. Think it needs a rebuild?

 

nope sounds decent to me.

 

yeah it should stop fairly quickly. as long as there isn't resistance...

 

ok, good. Ill figure out what kind of turbo it is, and if its worth it to make my own turbo kit outta it

 

Post some pics of it and we'll tell you what it is.
Also, was the turbo lubed w/oil? If there's no oil in it, the freeplay characteristics will be a little different. Splash some oil in there and spin it again... should freewheel a little longer maybe.
However, spinning a turbo doesn't necessarily tell you if it's good or not. What kind of play does the shaft have. Can you wiggle it side-to-side (even a little bit), in/out maybe? Post pics... with the housings on and off so we can see the whole of both wheels.