OK. If you are sitting on a hill more than 15 degrees, if you do it will make that grinding sound. in most car booklets say on a Hill 15 degrees or more put it in neutral than apply the emergency break. and you do not need to be at any speed when putting it into park.
if it is in fact the starter, it is probably engaging the flywheel. starter may be faulty.
What would cause a grinding noise after a tire is replaced and the brakes are not worn?
A bad transmission. The sound is from metal grinding on eachother.
You probably have something wrong with your engine, or brakes. You should really have that checked.
bad rotors
your clutch may not be fully engaging
wheel bearing
Lol everything! When you run an engine without sufficient engine, all the moving parts get hot and wear increases. And this may cause distortion from the extreme heating and cooling of the moving parts. Distortion means they are not the right shape and so it grinds as it tries to do what it used to.
I have been told it may be the Alternator eeding a refurb
your barrins in the wheels
Engines work best in a limited range of resistance and rate of rotation. Gears makes it possible to have the engine running in that range (almost) regardless of what speed the vehicle is moving at.W/o gears the engine would first struggle to get the car moving(where the resistance is too high), and once moving, the engine would struggle to get the car to speed, as the engine soon wouldn't be able to spin any faster.
It could make a grinding type noise when moving slow. A "whirrr" type whine when moving faster. The grinding noise may change to a clunking noise when turning the wheel. Any of these noises means "fix me now or else."