Here is the situation: 235 engine with a TC 350 auto transmission. 12 volt starter with solenoid, not a floor button. Original starter would sometimes rotate, most times just a loud clunk. Took it out/ apart per Nates advice, cleaned it up reset one of the brushes, reinstalled and same thing but now has almost a grinding noise when it does rotate. Used a jumper switch eliminating the ignition switch and still same thing. Changed out the starter with a rebuilt and same thing even with the jumper switch. Now the new starter came with some shims, I’ve never used shims before and the old one didn’t have any so did not install any. With the auto transmission there is know way to check the mesh between the starter and fly wheel. So could this be the problem? The engine turns over by hand but may be a little tight even with the spark plugs out but seems to be normal. It was supposedly recently rebuilt. Any suggestions? Thanks, Frustrated.