There is clutch material in the Torque Conveter ... you should not have reused it. What was your post install/pre-start checklist?
IIRC, you should have filled up the trans with fluid through the dipstick (approximately 12 quarts total). Started the car and the move the gear selector from Park to Nuetral, waited a few seconds, the move into each gear (foot on the brake of course) for a few seconds (5-10), working your way down through all the gears, then back. Manually, each gear should engage. What you are doing is working the fluid through the transmission & valvebody. Only after doing this, should you have tried to drive the car.
--> Before the work was done, the trans would "slip" and after the motor running for 20 to 30 minutes the trans would not engaged at all. When I drove it around the block the other day, at one point I gave it about half throttle to get it going and then slowly went towards full throttle (only for a few seconds). The more throttle I gave the more it "locked up". Your point is well taken that the TC needs to be replaced.
I did the exact procedure you listed...fill the trans, work through each gear with the brake on, etc. I did this while it was still on the jack stands. When I let off the brake in each gear the axles responded immediately. When I put the car on the ground I did the same procedure again. Then when I let off the brake the car didn't move. It only moved when I gave it 1/2 + throttle. All of this has led me back to the valve body, but I am open to suggestions (like the TC, thanks!).
Gary