I have a new vibration coming from the driveline on my 01 4.6 HSE. It only happens on freeway at speed and when I back my foot off the pedal right when the engine isn't pushing or pulling on the driveline. Right at that point where there is no load on the driveline does it start to make a noise like I'm driving on the new rumble lines they have put on the highways lately. You know the one that looks like a bulldozer drove down the road on a hot day and left track marks in the asphalt. I just put a brand new front driveshaft on from AB and that didn't solve it ( I needed the drive shaft replaced anyway because the previous owner didn't know what grease was for. ) I pulled the truck up on the ramps yesterday and checked the rear driveline for play and it's tight and has new u-joints so thats not it. I took the inspection plate off and checked the bolts holding the flexplate and they are tight as well so anybody have any similar problems in the past that would help me diagnose this latest irritation I would appreciate the input. Who out there thinks I have a broken flexplate or blown torgue converter, Thanks, T.