I was driving in 2WD when all of a sudden my blazer started shaking and i heard a noise like a jackhammer. The noise changed in tone and pitch when i accelerate and dissapears after a few seconds when coasting. the first thing i thought was U-Joint but after putting in a new one in it still persisted. I changed the transfer case and rear driveline recently so im wondering if i might have installed something wrong or if its something else completely.