so I have a non Y-BLOCK question involving the c-4 in my 57 f100.A few months back I had my c-4 rebuilt by a shop.It lasted 5000 miles when the main seal behind the torque converter started squirting fluid out.I tore it all down and found the main bushing to be fried.The torque converter is also fried ,has gouge marks indicating it was woppling. My flex plate isnt bent,and had everything tightened down correctly.Checked to see if the torque converter stud extensions were all the same length[the c-4 adapter has stud extensions].Everything seems to be true.I even bolted the torque converter back up to the flex plate to check to see if everything is true.I used a dial indicater to check while I turned the engine by hand ,and it seems fine.What could have caused this?The c-4 is still under warranty,but I dont want to tear this down again after another 5000 miles.I might just switch back to a manual trans,as this is the third time I had to take this trans out.Has anybody else had this problem?

55 fairlane gasser 312 /c4, 57 f100 292/c4, 52 mainline gasser 302/t10 4speed