Hi there. My B7 4.2L V8 has developed an engine bearing noise

it's progressively become louder over the last few weeks. I get it between idle and 1800rpm, even when stationary. Turning the A/C off, rocking the steering, or depressing the clutch makes no difference. When I'm in 2nd or 3rd I can feel the vibration through the pedals and steering wheel, especially coming down on overrun below 1800rpm. I've run it up on a ramp without the serpentine belt- still the same! So it's not alternator or tensioner, ( which is exactly what it sounds like). I've got a fellow mechanic to hold the revs at 1500 and listened with a long screwdriver to my ear, to the water pump, power steering pump and as best as possible to the A/C compressor (it's buried, and difficult to get at). It does not seem to be any of these. However I noticed that the resonance and vibration could be felt (quite violently) coming from both oil cooler pipes coming out of the engine to the front oil cooler mounted at the radiator.
This leads me to think that the noise is being generated from the Gear Plate/ Gear Module associated with the auxiliary drive chain. This is what drives all the external pumps- a/c, water, p/s. It also drives the oil pump which I believe has a gear driven counterbalance shaft within it.
Has anyone else had problems with the Gear Plate or oil pump on a B7