Im sorry but I cannot see any pictures in this thread.

anyway - you mention that it does not change pitch when revved up, you can comfortably leave out the PS pump from the noise cause.

__________________
2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)