Nissan Repair: 94 nissan altima, crank shaft, nissan altima

Question
thanks..what do i need to fix this?is it the starter or the flywheel?thanks alot y'all
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-----Question-----
i have a 94 altima that wont start sometimes.when it does it makes a grinding sound,when it doesn't make any sound.but the radio plays and headlights work.i took the starter off and had it checked,they said it was fine.also i replaced the switch at the clutch.possibly the crank shaft sensor.thanks everybody
-----Answer-----
Mark,

The grinding noise is the starter drive.  The starter may be fine but the drive that pushes the gear out to the flywheel is going out.  That is what I find when you hear grinding.

Answer
Mark,

Replace the starter.  If the grinding has not been going on too long the flywheel should be fine.  Only way to know is replace the starter and see how it works.  If it continues to grind then the flywheel was damaged and that would have to be replaced too.  Not too common so replace the starter and you should be fine.