Sounds like a separate problem. May be the selinoid on the starter hanging up.
Yes, the differential can make a grinding sound.
wheel barings
The grinding sound means that the brake pads are worn down to metal and that sound you hear is metal to metal. you need to have the pads changed, the problem is that you will more than likely have to change the rotors also. The way to avoid this in the future is when you notice your brakes are making a squealing sound that means that the pads will need to be changed soon.
depends on where the grinding id coming from
A bad transmission. The sound is from metal grinding on eachother.
Bad wheel bearings usually cause a grinding noise, and are known to only cause it when turning.
Grinding
The 1996 Saturn more likely has a blown head gasket. The gaskets will give this problem. If the head is in doubt it can be checked for warpage.
it would depend on how long it was before you changed the oil, the more you drive it the metal sound will disapate.
The "awful grinding sound" might be a problem with your power steering
Even though the brakes were recently changed, I would have the brakes taken apart and inspected. Something may have gone wrong.
Usually it'll be a grinding sound.