Rick,
1. Stupid idea first .. does it have
oil in it? GM Synchromesh spec stuff?
2. Is the shifter free to move into reverse? Mainly, is movement restricted by the edge of the tunnel cutout? Or does the shifter boot limit movement to the lower right corner?
3. You don't say what kind of throw out bearing you have. If it is adjusted incorrectly, you will not get complete clutch disengagement, thus balky shifting.
4. Pedal throw may not be enough .. unscrew the master cylinder clevis at the bell crank a few turns.
Yes, maybe the tranny is defective. But you need to eliminate all other factors first .. ask me how I know
Good luck,
Sam