David J D Todd

Hello and help please. I am in South Australia and need some advice. I have a 1952 Pontiac Chieftain coupe 4.4 litre straight 8 with the 4 speed dual ratio automatic transmission. I have just finished a total off chassis restoration and have a problem with the transmission. I can drive the car up to 30 miles with it performing beautifully then all of a sudden I have no gears. It will not shift into any gear. I have checked the trans fluid level and that is okay. Is it possible that the torque converter could be causing the problem? I just don't have any answers. This has happened twice and it is a real puzzle. Can anyone please be able to help me with this problem? Thanks, David Todd