Hi guys,

I hope somebody can help me. I have a 99 Expedition EB, 5.4. When under heavy load/acceleration the driveline feels like it is slamming in and out of 4 wheel drive. How do I go about troubleshooting it to try to fix it. It also happens to a smaller degree when slowing down. Where is the sensor that controls the automatic 4X4. It seems to be getting worse as time goes by. Is it possible to put a switch in to override the automatic 4x4 so it won;t happen? Truck has 225,000 miles and this is new.. It isn't the normal transmission clunk from what I have read. It seems more violent than that.

Thanks for your help