From what you are describing the sound you are hearing is the whine of the hydraulic drive cleaning fan. When you sit inside the cab of the 8010 the cleaning fan sound is distinctive from other sounds even the engine. If you have only heard an 8010 from the sidelines you don't know what you are missing. The sound is different when not harvesting and if you stand beside one when it is idling you would swear the engine is much larger than the 10.3 L size it is.
The 8010 has the quietest cab of any combine I have been in the last 30+ years, fan whine or not.