I agree with LVRockCrawler. It is most likely that your throwout bearing is causing the squeeling noise. The grease has probably dried up and you will need to replace it. It happened to me on the way to Fort McCoy Wisconsin with the Ill National Guard in a 1973 Datsun pickup. It ran fine all the way from Illinois, until I turned on the exit ramp and had to engage the clutch. Every time I pushed in the clutch there was a horrible screeching sound. I ended up changing it out in the parking lot of my BOQ. Got a lot of looks, but hey, when you don't have any extra money, you do what you gotta do.
Good Luck