Problem Solved.... I shared this thread with the the Independent Mech. Once he got under the D1 he did discover that the front propeller shaft u-joints were completely dry of grease and were pretty much used up. He replaced all front u-joints and serviced the transfer case. He charged me a Total of $360 for the parts, repair and service which I felt was a fair price... Vibration and clunk is now gone and the D1 is back to it's smooth ride again. The Independent Mechanic was very receptive to the information provided by several forum members here. Thanks to everyone for your help. John