If I remember correctly, if you are working on a late 87 or 88 model 700R4 or 4l60 "same thing" they drilled the bleed hole bigger than the apply hole in the pump and there was some reverse failures because of that. So when I run into one that has the small apply hole, I will plug off the original bleed hole in the piston and drill on the other side that already has a hole started but not drilled through with about a .60 thousandths bit.
