What in the world causes the transmission on a 97 4.6 v8 to shudder?!?! feels like im running over a wash board or rumble strips. Its done it since i bought the car in 2008. I have to pull out of my driveway like a bat out of hell to keep it from shuddering. Every time it shifts into O/D, it does it. Even disabled O/D with the button on the gear selector and it still does it between 3rd and 4th gear. In city driving (stop and go) it shifts really hard. Sometimes sounding like you bottomed the car out. Shudder fixer or any other additive is only a temporary fix. I want to know what causes it and what will fix it for good! Does anybody have any idea? Is this shuddering gonna hurt the car?