My TJ has done this since I have had it. At first I thought it was the brakes but after replacing the rotors and pads in the front and the rear drums and shoes there was no change at all. Jeep rides smooth when accelerating at any speed but when coasting or not pressing on the gas pedal I get a strange grinding/vibration feeling that seems to come from all over. I feel it in the seat, dash, wheel, everywhere and its enough to make the change and my sunglasses shake in the console or spill a drink in the console. If I am in a parking lot and put the Jeep in drive and let it roll I feel it, if I turn the jeep off and roll I feel it, basically anytime I am going under 10mph I feel it unless I am pressing the gas. I have 31" Duratracs and most of the research I have seen points toward the tires but on my previous JK with duratracs I didn't feel anything like this. It doesn't effect performance and doesn't seem to be getting better or worse so I have just ignored it but I don't like not knowing what it is. It did it before the lift and after didn't seem to make any difference. Motor mounts look good, Transmission mount could be replaced, I went through the diffs and didn't find anything out of the ordinary, Brakes are all good, hubs don't make noise, Drive shafts are rusty but there is no play in the U joints, Engine runs smooth, trans shifts smooth, I'm not sure where else to look other than tires but these are less than a year old or maybe something binding in the TC. Any recommendations?