1998 Chevy Cavalier starter noise

Engine Mechanical problem
1998 Chevy Cavalier 4 cyl Front Wheel Drive Automatic 126K miles

Hey pros, I've got a tough one for ya. I'm having a starter problem I need help with. When we try to start the car, SOMETIMES we get a grinding noise between the starter drive gear and the ring gear. Sometimes we get no response from the starter until we move the shifter to the neutral position. It starts in park about 75% of the time. We replaced the starter thinking it was bad but it's doing the same thing. Also the shifter is slightly off from the gear indicator on the dash, meaning there is some misalignment. Someone suggest shimming the starter but it doesn't make the noise all the time and tonite when we tried to start it, the starting electrical system wouldn't respond in either park or neutral for about 20 trys and when contact finally was made-in park- the noise didn't come at the end of the start cycle but during the start cycle as well. The next time we tried to start the car it started fine-in park- with no noise at all.