A humming bird
idle air control valve
Wheel bearing.
The fuel pump is engaged.
Certain types of tires may cause a brief humming noise after your initial acceleration. The transmission may also cause a brief humming noise.
I have a whirring sound in my ears Can you tell me what is causing it?
The roof rack or lauggage rack may be catching wind and vibrating. If it has adjustable cross members slide them toward the back of the van and see if that helps.
Wheel bearing
That will be the engine. A necessary component in a motor vehicle.
Low fluid level.
bad wheel bearings
Could be a bearing going bad.