I have a 2006 Expedition Limited with 96k miles. I'm having problems at lower speeds, like 40-50 miles per hour, with it downshifting and then upshifting back to back. It doesn't do it at higher speeds or if I turn the overdrive off. Do these models still have the downshift cable or could it be something else causing this? I have already changed the.fluid and filter and nothing was in the pan. Any help or ideas would be greatly appreciated