high pitched sound when driving

[Ground Hog]

I have a high pitched sound while driving. It almost sounds like a turbine. I think its coming from the driveline or wheels. The sound picks up as I speed up and goes down as I slow. When I shift into neutral while moving noise continues. When stopped, the noise stops. Thoughs??

[mearstrae]

Sounds like it could be the transfer case. At long distance it's tough to know just what you're hearing, but a lucky guess on my part might help.

'99 Disco II
'95 R.R.C. Lwb (Gone...)
'76 Series III Hybrid 109
'70 Rover 3500S