Throwout Bearing???

[cadillac531]

Armed with my new fuel pumps and tires, I took the Beast for a little trip out of town last weekend. She ran like a champ, through the rain, and up the hills and mountains with the AC on and the cruise on, it pulled down 23.2 mpg. I was pretty happy, as this makes the ZR my most fuel efficient vehicle

Anyway, when I left my folks' house to come back home, the trans made a high pitched bearing-like sound just as the clutch engaged. It did it as I would engage reverse and as I would engage first. I took it around the block before heading on back, and when everything warmed up, the sound went away and didn't come back.

I started the car again today and it gave me the same sounds, I rocked the car front and back with the clutch and after the third time of doing this, the sound stopped and the clutch engaged quietly like usual.

Can anyone describe to me the sound a throwout bearing makes? The trans shifts fine, and there are not any other audible sounds other than the ones a ZF usually makes.

Thanks.