Does it sound like a bearing telling you "Grease meeeeeeeEEEEEEEEEEEEEeeeeeeeeee!!!!" Seriously though, it could be a throw out bearing or an idler bearing gone dry. I'm not sure which one your GT has. Might want to ask in the "Bolens" section in the Forums. (tractorbynet.com/forums/bolens) Maybe you could try checking over at http://www.mytractorforum.com in their Bolens section too, if you can't find an answer here.
/ Bolens 900 high pitched squeeking when I press the clutch/brake
I would normally agree with Mace Canute's evaluation, but I think that Bolens has a belt drive and you are probably getting some squeal from the belt or an idler pulley may be going bad. Mace Canute's suggestion to post where there are more expert opinions is exactly what I'd also suggest. Someone who knows the details of your drivetrain can give you much better advice.