I have a 97 F-150 ext. cab 4x4, 4.6L with some transmission trouble. When it downshifts, say from OD to 3rd it's kinda hesitant and shakes pretty bad, i don't know if that is considered shuddering or not. The truck only has 66000 original miles on it. I changed the tranny fluid at around 56000 miles, but only in the pan. This fixed it for a little while, but when I started pulling a boat with it, it started acting up again. Sometimes when the truck is cold the tranny makes a squealing sound when up shifting. I hope that I don't need a new tranny, (and can't afford one), so any and all help is greatly appreciated.