I've never driven another D-90, so I don't know if what I'm hearing is normal or not.
From about 20mph and up, there's a high-pitched whine coming (I believe) from the transfer case. If I lift my foot off the gas pedal, the noise instantly goes away. If I keep my foot off the gas, the rig starts to slow down and the noise comes back. If I put my foot back on the gas, the noise comes back.
Is this normal or does it sound like transfer case is in need of repair?