Since i been lurking here i was wondering how to maybe fix the vibration problem. From my expierence in the shop synthetic rear end lube stinks. I believe the new ford's use this. I was wondering b/c alot of the vibration guys vibration problems have been fixed with new clutch packs. I was thinking to myself and wondering if draining the rear end fluid and replacing it with regular old 80w90 gear oil and a bottle of ford's friction modifier additive would help at all, b/c it did wonders in the rcmp cars here b/c the rear end were going due to the synthetic gear oil and the gmc rear end's to. Just a suggestion to all to see if it may help out.