1998 TJ 2.5. I am pretty sure the throw out bearing and possibly the pilot bushing is bad in my TJ. Random bad vibration around 3000 rpm while shifting. Feel it in the pedal and body. However, when the Jeep is in 4 high the vibration is absolutely horrible. Just while reving to 3 or while shifting. Cruising is fine. Why would the vibration be so much more pronounced in 4 high? Just because extra driveline is engaged?