2001 Shifting Problem

I have a 2001 Cavalier which was fine and then it became very difficult to shift into gear. I bled the Slave Cylinder and the car was fine for a couple of days and then the problem returned. I see no signs of leaking fluid and have never really had to top off the resevoir more than a little. Any ideas on being the Slave Cylinder and/or Master Cylinder? Thanks for any help.

I was able to locate the problem. I pulled the transmission and discovered that the slave cylinder blew apart. I replaced that and the car is back to normal again. I hope this may help another Cavalier owner someday.