I've had this problem for a while now and I'm hoping one/some of you can help. The 4WD system appears to work fine, ie on launch it engages also showing on the torque split gauge. Now if I'm cruising along at about 60-70 mph and go over a fairly harsh bump then the car will vibrate like you're running over rumble strips. The torque gauge will also hover around 10-20 until I come off of the throttle, then the vibration will stop and the gauge will return to 0. Any ideas.