Can some one tell me about the system that keep the shifter lock when the engine is off, like in park. Then release the shifter win the engine is runing?. Thanks
Since you didn't tell us what the problem actually is, we have to makes some educated guesses here...
If I'm reading this correctly, you may be asking about what keeps the shifter it's self locked when you turn the key off.
If so, that particular lock is in the steering column.
What keeps your transmission in any particular 'gear' is called a 'Manual' valve. (Short for Manual Shift Valve)
That Manual Valve engages the Parking Pawl LEVE was talking about when you shift into park.
If you are asking what keeps the vehicle from rolling away, LEVE is dead right about the parking pawl and it's in the back of the transmission case.
If you are having problems keeping your transmission in any particular gear, there is a flat metal spring detent that makes the 'Notches' you feel when you shift through the gears...
If this spring breaks or the roller on the end becomes dislodged, you shifting between gears will become very rough, or you won't have any resistance at all between gears.
Anyway, explaining the problem in detail is usually the easy way to get an accurate answer here.
There are some really skilled guys when it comes to diagnostics here!