RockKrawlerKris

Hey everybody, Ive owned my 2000 Grand Cherokee for over 3 years now and have had an amazing time with it, can't really complain to much about it, if it breaks down, I fix it and I'm on my way, it's a Jeep thing right lol well I'm now running into a problem I can't fix, I'm a mechanic myself and I've had plenty of other mechanics looking at my jeep trying to determine what this noise is that I'm hearing when I drive, it's coming from the midsection of my floor, I'm pretty sure it's the T- Case, but I wanted someone else opinion. When I give the jeep some gas the torque from the engine stops the noise but once I take my foot of the gas it starts to make a noise that sounds like a helicopter, I replaced the u-joints on my drive shafts but it still makes the noise. Please help?!