when I let off the gas, I hear a roaring noise other than the 33' tires, I pulled the rear diff and put some 90w synthetic, not an abnormal amount of metal on the magentic fill plug, gears looked fine, tranny is shifting smooth, does the transfer case oil/fluid seperate from the transmission? anyhow, the u joints are the non greasable kind(oem). Also, when i let off the gas and tap on the brakes, there is no changel. ANY IDEAS???