904 help, won't move

Thanks for the replies. I have tried moving the wheels in neutral, spin easily. Gauging the test ports is in the plan, just need to get the equipment together. The truck will move a little when revved high (3 to 4K). The fluid level shows high even though I'm actually still a quart low from what the book calls for. Is there something in the valve body that would stop flow to the torque converter? I can feel the drums engage when shifting in and out of gears.