Tomw, While your explanation is pretty reasonable, I have to disagree with several points. I have had problems with multiple Aerostar, all of which had the A4LD, and low fluid will cause they very problem you describe and if ignored will rapidly cause additional problems. The fluids original color is red, not pink or brown, and not purple. As the friction material wears off the bands and clutches, much of it is too small to be trapped by the filter, it does not plug the filter and restrict flow, but it does basically sand blast the internals of the transmission. Because it is too small to be trapped by the filter, the only way to remove it is replace the fluid that is carrying it. The general idea you put across is correct though, just would rather see the details cleaned up a bit.