Oh man... *braces self* I'm no expert by any means so I'll try and explain this as best I can. I was driving my auto 98' 3.0cl to a meeting and as I pulled into the parking spot, a whine started up from the engine at almost the exact time I came to a stop. I immediately turned the engine off, fearing a timing belt snap or something destructive like that. I started it up again and the whine/moan continued. I opened the hood, and as you're facing the engine bay, the moan is coming from the left side of the engine, where all those gears and pulleys are... I drove it home... slowly, and noticed that it is loudest when in drive while stopped at a stop sign or something, but you can still hear it all the rest of the time. It's at around 97k miles. I recently had the EGR valve replaced (and man did it need it... so much carbon buildup it's hard to believe it worked at all...). The timing belt has NOT been replaced yet. Thanks for any help.

 

have you checked the timing belt grooves? might just need a new timing belt.
if not, do any of the pulleys wobble or look like they're spinning weird? can you pinpoint one pulley?

 

Could be the alternator, mine emitted a whining sound before it went. Alt is located on the passenger side.