locked or not?
 

well i got the truck from a friend ... he said it was locked but im not sure. the crank spins almost the full 360 degrees but then it just stops... ? also the theft lock is on so i can start it with the key.. it has the original key... any ideas ? thanks .

well if it stop just before 360, sounds like a valve has dropped. Can you spin it backwards more then 360?

or a rod is hiting it

hitting the crank when it spins i had a explorer that did that

you need to pull the motor apart, no security deal like that.