The alternator was changed last yr,noise is still there.
I thought maybe power steering pump or water pump,even though neither are leaking,or giving us any troubles.We took off the W.P./power steering belt,and started it up...the low growling/moaning noise is still there.Its there as soon as the car starts,and stays on until you shut the car off.It's been like this for several yrs.Sounds like it may be internal.I need your help guys...name that mystery noise.I'm including 2 short vid clips(although both are dark,the noise is pretty clear).On the 2nd clip,listen after he revs it up,and the rpms start to come down.
Any help is appreciated.
View My Video (http://tinypic.com/r/zlggn/4)
View My Video (http://tinypic.com/r/mmyddt/4)

The engines oil pump would be the only thing moving fluid internally to make the growling noise. Have you tried checking your oil pressure? *Refer to a manual and it will tell you how to much easier than I can explain.

*Just my 2 cents again. I have a TransAm with a 434 SB and it's timing chain before I changed it had little play (My timing would change eratically) and it made a growling and slight whine noise. Perhaps your timing chain could be the culprit?

My alternator whines like a newborn. It'll make you look twice thinking it may be turbo. lol. I've been through several and they whine as well.

When my alternator was going bad the first time it sounded like a growling bear as I guess an internal bearing went bad?