Toyota Repair: 1999 Toyota Camry wont start, toyota camry, bench test

Question
I own a 1999 Toyota Camry 4 cylinder - it started to have trouble starting the batteries terminals were dirty so I removed them and clean them one broke so I replaced them with new ones and cleaned both post before I reinstalled them. Now my car won't start. Check the battery it has 12 volts. Put my charger on just to be on the safe side. The starter is making noise. Trouble shoot system came to the conclusion the starter relay is bad. Replaced relay and the clicking sound of the starter no fully engaging stop. But the starter still will not fully turn the car engine over. I then jump out the starter ran a hot wire right to the starter with same result won't fully crank. Removed starter and bench test works great. Put back in same thing. Finally I replaced the starter with a new one and still have same problem will not crank the car over. Have check the engine and it is not seized and check the fuses.
Please help this thing has me puzzled   
Thanks for your time Bill


Answer
Does the starter make a loud spinning noise but won't turn the engine over? Describe just what the noise is it is making.
There is a possibility that the flywheel ring gear is damaged but I'm not sure from what you have told me so far, please provide more information by answering the above questions.