86 240 wgn The noise happens at all speeds. It starts when the cars first moves and builds speed with the speed of the car until it becomes a turbine like whistle. sounds like a jet engine starting. It does not change tones with RPM changes, {auto trans} It does note change tones with a gear change, even coasting in neutral. The oil in the Diff is good, i changed it and there were no flakes, trans runs strong. I can not figure out where it is coming from. no grinding noises. at low speeds sounds like it is coming from the rear of the car. higher speeds i can hear it in the gear selector console. no leaks. all fluids are good and correct colors. Turning side to side to load different bearings has no effect. any ideas?