Problem with my A-904-A Torqueflight Transmission

Hi All!
Any help or advice would be greatly appreciated.

The Original transmission was pulled from the car and modified around 1990 when I started the restoration. The car is a 1968 Dart G.T. When the transmission was out I installed a shift kit, deep tranny pan kit and Mopar 2200-2400 stall torque converter. I filled the transmission with Dextron and reinstalled it back in the car. I also change the rear axle ratio to 4.10.

Fast forward to today. I tried to put the car in gear for the first time. With the car off and up on jack stands I spun the rear wheels by hand and made sure neutral was really neutral, park was park etc. I also adjusted kick down linkage. There was no other adjustment made to the transmission.

I started the car in park warmed it up for 5 minutes, went through the gears slowly and stopped at neutral. When the transmission pan temperature got to 200 degrees, I checked and adjusted the transmission fluid level.

The next thing I did was to check if it would go into forward and reverse gear. I first noticed the lack of torque going into all gear positions, it felt like the engine was not running, no positive engagement of the transmission. the wheels start to turn at about 2000 rpm and the wheel speed is only about 3 to 5 rpm.

Very interested if anyone has experienced this.

Thanks