well my mechanic told me he put the thing on a rack and started out at 0 mph and went all the way to 60mph with listening equip all over it and said he cant pinpoint the problem thats making the roar. Its happing aroud 40 to 50 when the rpms drop back to between 1500 and 1900. as soon as i release the throttle it stops or if I get on it and get those rpms up it stops . Just change all diff and transfer case fluid and now a little better. I'm gona go with some new u joints now and hope this works. I guess I'm just changing em out in hope it fixes the prob.