The design problems are an example of how poor engineering can exist when we depend too much on computers and throw common sense out the door. Most washers under such loads will try and spin with the load. As the clutches wear, the washer when it spins gets caught in the webs of the main case and breaks. Sometimes broken pieces of the washer will jam in between the case an direct piston causing the unit to get stuck in 2 modes and burn up.
The new washer has tangs that lock to the piston and prevent it from spinning. The old washer lacks the tangs. If you look closely at the picture you will see that the old washer had some broken ends. This problem was corrected in 1986 but some washers had poor heat treating and cracked anyway. We currently make this part for General Motors and have corrected the heat treat problems.