Ford Repair: 1982 ford 3.8 ltd, fly wheel, flywheel

Question
the starter grinds, if i replace the  starter drive its ok,
for a while, then it starts to not engage,unless i spin the motor by hand, iam thinkin bad fly wheel maybe,to try and cure the problem u tried to shim it, and it worked great for about 2 months and then it went back to the same thing,
when i look at the bad drive the teeth on the end are chewed up down about 1/4 inch, i have owned another car same make and model with the same problem any help would be appreciated thank you

Answer
pull the starter off and look inside at the flywheel as you turn it around there will be six areas where it mainly stops if the teeth are really rough on the flywheel in these areas it will keep eating starters-you will need to replace flywheel and current starter if it is rough-be sure and use good quality parts. good luck.