Whirring sound and no power.

sounds like a bad starter or teeth off of flywheel try starter first.

Is this occurring when the vehicle is already running? If it won't start, yes, check the starter first. If this is occurring when the engine is running/you are driving, it sounds more like a transmission issue, perhaps front pump or torque convertor.

I have the same problem. A mechanic said it's the transaxel pinion bearings. The noise isn't very loud or anoying so i'm not planning to repair it. Hope this is of some help. BSD0168

As for the lac of power issue, sounds like a transmision slippage problem. BSD0168