Help identifing source of noise

[SWLA]

Last 2 days I have noticed a new high pitched noise. Occurs at low speed, braking or turning. Lasts about 5-10 secs, sort of fades out. If I'm stopped and let off the brake and begin to roll foward at idle, or slow to a stop from a low speed, I hear it. If I turn sharply at a low speed I hear it. No effects on braking or steering performance noticed. I checked the power steering fluid level with the engine hot and it was low. I haven't seem any evidence of a leak in the driveway. I have not had a chance to inpect the engine bay for a leak either. Plan to check the cold level this evening, if its low I will top it off.

Am I barking up the right tree? Doesn't sound like what I've heard in other vehicles with PS problems before. Even if replacing the fluid solves the problem, it going to the dealer to see why its low. Is this what the folks with hydroboost problems noticed? I definitely hear it, so I know its not a loose nut between the steering wheel and the seat :D

[Dave_WB3FYV]

Wonder if it could be the brake pad wear indicators.
I haven't looked to see if they still put them on, but a little bent piece of metal on one shoe of each caliper will scrape the disc when the pad material gets too thin. My '93 would do that after 60,000 miles, when turning sharply at low speed I guess everything flexed enough for the scraper to make contact. The very high pitched sound (kinda like finger nails on a blackboard)prompted the repair in a hurry!
Might be worth a look, you have an '01 - do you drive a lot in traffic? got a lot of miles on her??

[SWLA]

Mackin,
I checked the PS fluid level again last night after the engine had cooled. Was at the cold full level, I'll check it a gain later today.

Dave,
I only have about 20,000 miles on the truck. Bought new in 10/01. About 60/40 highway to city driving. It really doesn't sound like brake wear indicators, at least not what I've heard in the past. Much more high pitched and not as loud. Doesn't have that screech quality, almost sounds like a tuning fork fading out.

Plan to try to to get the truck to dealer this week anyway for the 3rd attempt to get the steering rattle fixed.