Starter made a grinding sound in motor and now just spins free

Starter soups but doesn't engage. Clicking sound: you hear it spinning with a click sound before it starts spinning. No grinding sound. The mechanism to engage the fly wheel could be faulty, probably it is seized, or battery doesn't have enough power to make the solenoid fully pull mechanism (check battery amps charge if low. You may need to look at the starter as someone turns the motor over and make sure it's engaging all the way to fly wheel.
Sometimes you may need to Shem or file down where the two bolts go into the starter too get it far enough into the starter casing to get it to engage.
Walld"

the only things that are rotating to give a grinding sound are
the crankshaft, cam shaft and starter motor
for the crankshaft it could be slipper bearings too tight and are now spinning in the caps, missing thrust bearing halves on the crank shaft
on the cam shaft -bolts behind the cam gear touching on the back of the gear
oil thrower disc in wrong and the edge is running on the cover of the timing chain housing
starter motor not in correctly and jamming the pinion in the ring gear while the motor is running( some 350 motors have a shim adjustment for the starter housing to block
It is difficult to say exactly but if you followed the workshop manual to the letter you will know what you missed

It sounds as if the starter is turning but not engaging so I'd suspect the clutch or the gear is loose or without teeth, but even without teeth you'd likely hear unpleasant grinding noises. I'd expect the clutch and starter are all one unit. (They are on a car where space is less critical than a bike.) Try giving the starter a bang with the handle of a screwdriver or hammer to see if it frees the gears to engage while you're trying to start it. If it starts, replace the starter. You should get a re-core charge if you don't bring in the old starter. (You do with cars.)

Many times a bad starter motor makes noise like clanking, clicking or grinding when crank the engine. Replace the starter. Sometimes, if the starter motor is grinding the gears on the flywheel, the engine will have a metallic grating sound when you first crank it. This type of starter noise is normally indicative of a starter motor that is worn and about to fail. If you do need to replace your starter this site looks like it has cheap prices, free shipping and great reviews http://www.buyautoparts.com/starter.htm

A bad starter will kill a battery real quick. If you can find a DC amp-meter compare it to factory specs, or similar car starters. A bad starter will make a grinding noise, or give false tries where the starter spins free without engaging the motor. Of course, a bad starter will not spin at all, just make sure the relay is working.

if the starter spins and grinds when you try to start the truck your starter is bad it could be a starter drive or other bad starter parts the problem with knewer cars is its just easyer to replace the starter then it is to rebuild then and more cost effective.

The teeth on the flywheel need to be close enough for the starter motor to catch them when it engages. If you removed it and now the starter just free-spins when starting then you may have installed the flywheel backwards and the starter motor cannot reach the teeth on the flywheel. If its making a loud grinding or pinging sound you may need to manually turn the engine a bit to align the flywheel.

The grinding noise is the starter hitting the fly wheel. This means that the starter is spinning but may not be engaging all the way. Your Flywheel is probably missing a few teeth now. I recommend replacing starter and flywheel. If you're on a tight budget then you could just replace the starter but it will cost you more in the long run.

if the starter is making grinding sound it not! however it could be loos and needs to be bolted up tight or there may be a bad power joint to the starter,, check for this also check all the earth leads off the engine to the battery, if its still grinding then its likely to be a dud starter you fitted,, the solenoid is not fully engaging the starter bog in the fly wheel teeth and it stopping short and then it spins up this is whats making the grinding noise, it can also make a right mess of your fly wheel ring gear,, so dont leave it to long to get it sorted out,

yes it has a key slot in gear when starter gear engages to start the key pops in to slot and locks in place to start motor when it returns it frees gear,have you ever herd that grinding sound when you dont thank your cars running and you try to start it,its a good thing it turns freely.