Grinding noise when trying to start
 

I have a 2002 LS 4 wheel drive just replaced distributor, rotor and cap but when you turn the key over it tries to start but then there's a loud grinding noise, is that a bad starter? In my experience's with a bad starter it's always been a whining or clicking noise, this sounds like the grinding you get when you try to start a already running vehicle, Please help!!

It could be a bad starter, but it could also be a bad flywheel ring gear. The best thing to do is to take out the starter, then rotate the engine by hand to inspect the ring gear. An easier way is to turn the engine over by hand maybe 1/4 turn, then try to start it again. If it starts, you probably have some bad teeth on the ring gear. If it's the same, you probably have a bad starter.