Squealing noise from transmission of 2000 silverado?

I have a 2000 silverado, V8 Standard tranny, it seams as though there is a squealing noise comming from the tranny, at first I thought it was my idler pully going bad, but this afternoon noon I coasted into my driveway, clutch in and I shut the truck off and rolled to a stop and i could hear the noise, and it seams as though lately its been hard to put it into 1st and reverse, any help would be awesome thanks