[FWDLK] '59 Belvedere powerflite trans problem

Hi all, my name is Don Haddock and I’ve followed the list for years. I have a problem with rebuilding my powerflite transmission. It started a couple years ago when I went to the 2013 Michigan National Plymouth Owners Club meet. When I would start off from a stop I would get a shudder as if a brake was grabbing. It gradually kept getting worse and I eliminated all but the trans. I finally pulled the trans and tore it down and other than being dirty I found no problem. My problem now is after installing it ,I lost pressure causing a delay going in gear. I found the front pump gear had worn into the front valve body which is just behind it. I figured I must have assembled that front pump area incorrectly. I got a new front pump and valve body and re-assembled the trans again. I was very careful to make sure the pump drive sleeve was aligned properly with the torque converter when installing it. After a few minutes of running the engine and filling the trans and a short ride, it is now doing the same thing again. My question is “What is causing this to happen ?” Am I doing something wrong? Can the torque converter be at fault? Any help will be greatly appreciated. I am in New Hampshire and I’m sure I’ll need another Valve body and possibly the front pump. Help