pull off the inspection plate and the starter and look at your flywheel. My starter needed A LOT of shimming down, like 5/32nds, yes, more than 1/8" so my starter was hitting the front of the flywheel and ruining the starter but not the rinbggear...very much. I got a new starter cuz it was toast in 1 month. In the end I had to take the solenoid off the new starter and keep trying differnt shims and manually pushing the starter gear in until fully engaged with minimum pressure. After I got that I hooked everything up and started it 20 times then pulled the starter off to inspect the wear pattern and noticed slight the marks in the valleys of the starter gear so I shimmed it another 1/32 which is the min spacing. The starter install instructions tell you how to do all of this, and so does your NAPA guy.
All in all, this 1 hr of work goes a LONG way to save you time and money. But it sounds like you need to get a new ring gear first, then do this.
andy