The AODs have a TV cable that controls the shift points, where the E4OD, and other electronic transmissions are electronically controlled based on the computer models aka MFM. Mixing transmission fluids can cause issues with these transmissions, i.e. mixing mercon III where mercon IV was used, mercon IV with mercon V was used, etc. , due to the additives being different between the formulations. Some have said that using a generic trans fluid can also be a cause of the trans failures, maybe because the quality control isnt as strict on the generic formulations. Either way pull the codes on the electronically controlled trannies for a starting point.