Yes.  Grace logins will be granted for 90 days beyond the expiration date.  For instance, if your password expired on December 25, but you were on vacation, upon your return, you still have until June 25 to log in to the domain with your existing password.  On June 26^th, if you attempt to log in but have not changed your password, you will be locked out of the domain.  You will then need to call your LAN Administrator or the Help Desk at 724-4357 to have your account unlocked and your password changed.