Why is my Automatic Transmission Failing?

Last week while driving in D4, the transmission started to slip to where the car would not go in any gear. The engine would go top speed, but the transmission just would not engage. Towed home. Purchased a used 95 AT from a local trusted wrecking yard, installed a new torque converter and o-ring, filled with a quart of Honda AFT. While at it I also replaced the axles and ball joints. I drained all old AFT from used transmission and pick it back together.

The problem: Start car and running great with front wheels off the ground. I put the car in D4 and we get the wheel spinning. Change gears to reverse. Still good. After about 5 minutes we get no movement from the tranny. Turn the car off for 5-10 seconds, we then have access to all the gears, then dies a few minutes later.

I have the service manual and read it like 10 times. I've checked the Lock up Solenoids (15.5 ohms and get a click when 12v is connected). No CEL lights or ODB0 errors in the system. I just don't know where else to check. Could it be a bad ECU or bad trans?