My wagon suffered from the AW transmission malady, klunky upshifts and downshifts. I did notice this happened only after the transmission warmed up, so i figured i would try a trans cooler. I added Seafoam TansTune and drove the wagon around 250 miles, then did a trans fluid dump and flush, added a Derale 8000 cooler and a Magnefine filter on the return line from the radiatior. There is still a klunk every now and then when the weather is very hot, but the improvement is noticeable. The most annoying was the shift from 3rd to 4th and that has all but disappeared. Car has about 150K miles, i recommend trying this before commiting to the "open heart surgery" change of the valve body. Hope it helps someone!!